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Tas M, Özdoğan K, Şaşıoğlu E, Galanakis I. High Spin Magnetic Moments in All-3 d-Metallic Co-Based Full Heusler Compounds. Materials (Basel) 2023; 16:7543. [PMID: 38138686 PMCID: PMC10744821 DOI: 10.3390/ma16247543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/13/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023]
Abstract
We conduct ab-initio electronic structure calculations to explore a novel category of magnetic Heusler compounds, comprising solely 3d transition metal atoms and characterized by high spin magnetic moments. Specifically, we focus on Co2YZ Heusler compounds, where Y and Z represent transition metal atoms such that the order of the valence is Co > Y > Z. We show that these compounds exhibit a distinctive region of very low density of minority-spin states at the Fermi level when crystallizing in the L21 lattice structure. The existence of this pseudogap leads most of the studied compounds to a Slater-Pauling-type behavior of their total spin magnetic moment. Co2FeMn is the compound that presents the largest total spin magnetic moment in the unit cell reaching a very large value of 9 μB. Our findings suggest that these compounds are exceptionally promising materials for applications in the realms of spintronics and magnetoelectronics.
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Affiliation(s)
- Murat Tas
- Department of Physics, Gebze Technical University, 41400 Kocaeli, Turkey;
| | - Kemal Özdoğan
- Department of Physics, Yildiz Technical University, 34210 İstanbul, Turkey;
| | - Ersoy Şaşıoğlu
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Iosif Galanakis
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patra, Greece
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Galanakis I. Slater-Pauling Behavior in Half-Metallic Heusler Compounds. Nanomaterials (Basel) 2023; 13:2010. [PMID: 37446525 DOI: 10.3390/nano13132010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 06/29/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023]
Abstract
Heusler materials have become very popular over the last two decades due to the half-metallic properties of a large number of Heusler compounds. The latter are magnets that present a metallic behavior for the spin-up and a semiconducting behavior for the spin-down electronic band structure leading to a variety of spintronic applications, and Slater-Pauling rules have played a major role in the development of this research field. These rules have been derived using ab initio electronic structure calculations and directly connecting the electronic properties (existence of spin-down energy gap) to the magnetic properties (total spin magnetic moment). Their exact formulation depends on the half-metallic family under study and can be derived if the hybridization of the orbitals at various sites is taken into account. In this review, the origin and formulation of the Slater-Pauling rules for various families of Heusler compounds, derived during these two last decades, is presented.
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Affiliation(s)
- Iosif Galanakis
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patra, Greece
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Li XZ, Zhang WY, Skomski R, Sellmyer D. A modulated structure derived from the XA-type Mn 2RuSn Heusler compound. Acta Crystallogr B Struct Sci Cryst Eng Mater 2022; 78:485-489. [PMID: 35702965 DOI: 10.1107/s205252062200333x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/24/2022] [Indexed: 06/15/2023]
Abstract
A modulated structure derived from the inverse Heusler phase (the XA-type and the disordered variant L21B-type) has been observed in rapidly quenched Mn2RuSn ribbons. The powder X-ray diffraction pattern of the quenched ribbons can be indexed as an L21B-type structure. Electron diffraction patterns of the new structure mostly resemble those of the XA-type (and the disordered variant L21B-type) structure and additional reflections with denser spacing indicate a long periodicity. Orthogonal domains of the modulated structure were revealed by a selected-area electron diffraction pattern and the corresponding dark-field transmission electron microscopy images. The structure was further studied by the crystallographic analysis of high-resolution transmission electron microscopy images. A model for the modulated structure has been proposed to interpret the experimental results.
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Affiliation(s)
- Xing Zhong Li
- Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA
| | - Wen Yong Zhang
- Department of Physics, University of Nebraska, Lincoln, NE 68588, USA
| | - Ralph Skomski
- Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA
| | - David Sellmyer
- Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA
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Mende F, Noky J, Guin SN, Fecher GH, Manna K, Adler P, Schnelle W, Sun Y, Fu C, Felser C. Large Anomalous Hall and Nernst Effects in High Curie-Temperature Iron-Based Heusler Compounds. Adv Sci (Weinh) 2021; 8:e2100782. [PMID: 34240573 PMCID: PMC8425906 DOI: 10.1002/advs.202100782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/29/2021] [Indexed: 05/22/2023]
Abstract
The interplay between topology and magnetism has recently sparked the frontier studies of magnetic topological materials that exhibit intriguing anomalous Hall and Nernst effects owning to the large intrinsic Berry curvature (BC). To better understand the anomalous quantum transport properties of these materials and their implications for future applications such as electronic and thermoelectric devices, it is crucial to discover more novel material platforms for performing anomalous transverse transport studies. Here, it is experimentally demonstrated that low-cost Fe-based Heusler compounds exhibit large anomalous Hall and Nernst effects. An anomalous Hall conductivity of 250-750 S cm-1 and Nernst thermopower of above 2 µV K-1 are observed near room temperature. The positive effect of anti-site disorder on the anomalous Hall transport is revealed. Considering the very high Curie temperature (nearly 1000 K), larger Nernst thermopowers at high temperatures are expected owing to the existing magnetic order and the intrinsic BC. This work provides a background for developing low-cost Fe-based Heusler compounds as a new material platform for anomalous transport studies and applications, in particular, near and above room temperature.
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Affiliation(s)
- Felix Mende
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Jonathan Noky
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Satya N. Guin
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Gerhard H. Fecher
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
- Department of PhysicsIndian Institute of Technology DelhiHauz KhasNew Delhi110016India
| | - Peter Adler
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Walter Schnelle
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Yan Sun
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Chenguang Fu
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
- State Key Laboratory of Silicon Materials, and School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
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Yu M, Li G, Fu C, Liu E, Manna K, Budiyanto E, Yang Q, Felser C, Tüysüz H. Tunable e g Orbital Occupancy in Heusler Compounds for Oxygen Evolution Reaction*. Angew Chem Int Ed Engl 2021; 60:5800-5805. [PMID: 33300643 PMCID: PMC7986729 DOI: 10.1002/anie.202013610] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/23/2020] [Indexed: 01/08/2023]
Abstract
Heusler compounds have potential in electrocatalysis because of their mechanical robustness, metallic conductivity, and wide tunability in the electronic structure and element compositions. This study reports the first application of Co2 YZ-type Heusler compounds as electrocatalysts for the oxygen evolution reaction (OER). A range of Co2 YZ crystals was synthesized through the arc-melting method and the eg orbital filling of Co was precisely regulated by varying Y and Z sites of the compound. A correlation between the eg orbital filling of reactive Co sites and OER activity was found for Co2 MnZ compounds (Z=Ti, Al, V, and Ga), whereby higher catalytic current was achieved for eg orbital filling approaching unity. A similar trend of eg orbital filling on the reactivity of cobalt sites was also observed for other Heusler compounds (Co2 VZ, Z=Sn and Ga). This work demonstrates proof of concept in the application of Heusler compounds as a new class of OER electrocatalysts, and the influence of the manipulation of the spin orbitals on their catalytic performance.
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Affiliation(s)
- Mingquan Yu
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Guowei Li
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Straβe 4001187DresdenGermany
| | - Chenguang Fu
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Straβe 4001187DresdenGermany
| | - Enke Liu
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Straβe 4001187DresdenGermany
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190P. R. China
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Straβe 4001187DresdenGermany
- Department of PhysicsIndian Institute of TechnologyDelhiNew Delhi110016India
| | - Eko Budiyanto
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Qun Yang
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Straβe 4001187DresdenGermany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Straβe 4001187DresdenGermany
| | - Harun Tüysüz
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
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Swekis P, Sukhanov AS, Chen YC, Gloskovskii A, Fecher GH, Panagiotopoulos I, Sichelschmidt J, Ukleev V, Devishvili A, Vorobiev A, Inosov DS, Goennenwein STB, Felser C, Markou A. Magnetic and Electronic Properties of Weyl Semimetal Co 2MnGa Thin Films. Nanomaterials (Basel) 2021; 11:251. [PMID: 33477868 PMCID: PMC7832844 DOI: 10.3390/nano11010251] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 11/18/2022]
Abstract
Magnetic Weyl semimetals are newly discovered quantum materials with the potential for use in spintronic applications. Of particular interest is the cubic Heusler compound Co2MnGa due to its inherent magnetic and topological properties. This work presents the structural, magnetic and electronic properties of magnetron co-sputtered Co2MnGa thin films, with thicknesses ranging from 10 to 80 nm. Polarized neutron reflectometry confirmed a uniform magnetization through the films. Hard x-ray photoelectron spectroscopy revealed a high degree of spin polarization and localized (itinerant) character of the Mn d (Co d) valence electrons and accompanying magnetic moments. Further, broadband and field orientation-dependent ferromagnetic resonance measurements indicated a relation between the thickness-dependent structural and magnetic properties. The increase of the tensile strain-induced tetragonal distortion in the thinner films was reflected in an increase of the cubic anisotropy term and a decrease of the perpendicular uniaxial term. The lattice distortion led to a reduction of the Gilbert damping parameter and the thickness-dependent film quality affected the inhomogeneous linewidth broadening. These experimental findings will enrich the understanding of the electronic and magnetic properties of magnetic Weyl semimetal thin films.
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Affiliation(s)
- Peter Swekis
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany; (D.S.I.); (S.T.B.G.)
| | - Aleksandr S. Sukhanov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany; (D.S.I.); (S.T.B.G.)
| | - Yi-Cheng Chen
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | | | - Gerhard H. Fecher
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
| | - Ioannis Panagiotopoulos
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece;
| | - Jörg Sichelschmidt
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
| | - Victor Ukleev
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland;
| | - Anton Devishvili
- Institut Laue Langevin, 38000 Grenoble, France;
- Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden;
| | - Alexei Vorobiev
- Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden;
| | - Dmytro S. Inosov
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany; (D.S.I.); (S.T.B.G.)
| | - Sebastian T. B. Goennenwein
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany; (D.S.I.); (S.T.B.G.)
- Center for Transport and Devices of Emergent Materials, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
| | - Anastasios Markou
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany; (P.S.); (A.S.S.); (Y.-C.C.); (G.H.F.); (J.S.); (C.F.)
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Yasin FS, Peng L, Takagi R, Kanazawa N, Seki S, Tokura Y, Yu X. Bloch Lines Constituting Antiskyrmions Captured via Differential Phase Contrast. Adv Mater 2020; 32:e2004206. [PMID: 33043519 DOI: 10.1002/adma.202004206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Much scientific capital has been directed toward exotic magnetic spin textures called Bloch lines, that is, Néel-type line boundaries within domain walls, because their geometry promises high-density magnetic storage. While predicted to arise in high-anisotropy magnets, bulk soft magnets, and thin films with in-plane magnetization, Bloch lines also constitute magnetic antiskyrmions, that is, topological antiparticles of skyrmions. Most domain walls occur as Bloch-type or Néel-type, in which the magnetization rotates parallel or perpendicular to the domain wall across its profile, respectively. The Bloch lines' Néel-type rotation and their minute size make them difficult to directly measure. This work utilizes differential phase contrast (DPC) scanning transmission electron microscopy (STEM) to measure the in-plane magnetization of Bloch lines within antiskyrmions emergent in a non-centrosymmetric Heusler magnet with D2d symmetry, Mn1.4 Pt0.9 Pd0.1 Sn, in addition to Bloch-type skyrmions in an FeGe magnet with B20-type crystal structure to benchmark the DPC technique. Both in-focus measurement and identification of Bloch lines at the antiskyrmion's corners are provided.
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Affiliation(s)
- Fehmi S Yasin
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Licong Peng
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Rina Takagi
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-0032, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Shinichiro Seki
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-0032, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
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Abstract
The spin-gapless semiconductors (SGSs) are a new class of zero-gap materials which have fully spin polarized electrons and holes. They bridge the zero-gap materials and the half-metals. The band structures of the SGSs can have two types of energy dispersion: Dirac linear dispersion and parabolic dispersion. The Dirac-type SGSs exhibit fully spin polarized Dirac cones, and offer a platform for massless and fully spin polarized spintronics as well as dissipationless edge states via the quantum anomalous Hall effect. With fascinating spin and charge states, they hold great potential for spintronics. There have been tremendous efforts worldwide to find suitable candidates for SGSs. In particular, there is an increasing interest in searching for Dirac type SGSs. In the past decade, a large number of Dirac or parabolic type SGSs have been predicted by density functional theory, and some parabolic SGSs have been experimentally demonstrated. The SGSs hold great potential for spintronics, electronics, and optoelectronics with high speed and low-energy consumption. Here, both the Dirac and the parabolic types of SGSs in different material systems are reviewed and the concepts of the SGS, novel spin and charge states, and the potential applications of SGSs in next-generation spintronic devices are outlined.
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Affiliation(s)
- Zengji Yue
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute of Innovative Materials (AIIM), University of Wollongong, North Wollongong, NSW, 2522, Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, North Wollongong, NSW, 2522, Australia
| | - Zhi Li
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute of Innovative Materials (AIIM), University of Wollongong, North Wollongong, NSW, 2522, Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, North Wollongong, NSW, 2522, Australia
| | - Lina Sang
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute of Innovative Materials (AIIM), University of Wollongong, North Wollongong, NSW, 2522, Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, North Wollongong, NSW, 2522, Australia
| | - Xiaolin Wang
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute of Innovative Materials (AIIM), University of Wollongong, North Wollongong, NSW, 2522, Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, North Wollongong, NSW, 2522, Australia
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Guillemard C, Zhang W, Malinowski G, de Melo C, Gorchon J, Petit-Watelot S, Ghanbaja J, Mangin S, Le Fèvre P, Bertran F, Andrieu S. Engineering Co 2 MnAl x Si 1- x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization. Adv Mater 2020; 32:e1908357. [PMID: 32452576 DOI: 10.1002/adma.201908357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/07/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Engineering of magnetic materials for developing better spintronic applications relies on the control of two key parameters: the spin polarization and the Gilbert damping, responsible for the spin angular momentum dissipation. Both of them are expected to affect the ultrafast magnetization dynamics occurring on the femtosecond timescale. Here, engineered Co2 MnAlx Si1- x Heusler compounds are used to adjust the degree of spin polarization at the Fermi energy, P, from 60% to 100% and to investigate how they correlate with the damping. It is experimentally demonstrated that the damping decreases when increasing the spin polarization from 1.1 × 10-3 for Co2 MnAl with 63% spin polarization to an ultralow value of 4.6 × 10-4 for the half-metallic ferromagnet Co2 MnSi. This allows the investigation of the relation between these two parameters and the ultrafast demagnetization time characterizing the loss of magnetization occurring after femtosecond laser pulse excitation. The demagnetization time is observed to be inversely proportional to 1 - P and, as a consequence, to the magnetic damping, which can be attributed to the similarity of the spin angular momentum dissipation processes responsible for these two effects. Altogether, the high-quality Heusler compounds allow control over the band structure and therefore the channel for spin angular momentum dissipation.
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Affiliation(s)
- Charles Guillemard
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
- Synchrotron SOLEIL-CNRS, Saint-Aubin, Gif-sur-Yvette, 91192, France
| | - Wei Zhang
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
| | - Gregory Malinowski
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
| | - Claudia de Melo
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
| | - Jon Gorchon
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
| | | | - Jaafar Ghanbaja
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
| | - Stéphane Mangin
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
| | - Patrick Le Fèvre
- Synchrotron SOLEIL-CNRS, Saint-Aubin, Gif-sur-Yvette, 91192, France
| | - Francois Bertran
- Synchrotron SOLEIL-CNRS, Saint-Aubin, Gif-sur-Yvette, 91192, France
| | - Stéphane Andrieu
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, 54500, France
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Král D, Beran L, Zelený M, Zemen J, Antoš R, Hamrle J, Zázvorka J, Rameš M, Onderková K, Heczko O, Veis M. Magnetic and Magneto-Optical Properties of Fe 75-xMn 25Ga x Heusler-like Compounds. Materials (Basel) 2020; 13:E703. [PMID: 32033201 DOI: 10.3390/ma13030703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 11/17/2022]
Abstract
Fe75−xMn25Gax Heusler-like compounds were investigated in a wide range of Fe/Ga ratios while keeping the Mn content constant and equal 25 at% in order to elucidate the interplay between magnetic properties and composition. Materials were prepared by arc-melting from pure elements and subsequently annealed. Experimental investigations were focused on magnetization behavior in a wide temperature range from 4 to 1000 K and magnetic field up to 9 T. Optical and magneto-optical (MO) measurements were employed to shed more light on the magnetic state and electronic structure of investigated materials. Magnetization measurements indicated that in the vicinity of stoichiometry (Fe2MnGa) the compounds are ferro/ferrimagnetic, whereas the Fe-deficient compound is paramagnetic and at high Fe concentration the antiferromagnetic interaction prevails. Theoretical calculations of corresponding ordered and disordered stoichiometric compounds were carried out and compared to the experiment on the level of net magnetic moment as well as magneto-optical spectra. This comparison suggests that the Heusler crystal structure, L21, is not present even close to stoichiometry. Moreover, the comparison of density of states (DOS) for ordered and disordered structures allowed us to explain missing martensitic transformation (MT) in investigated materials.
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Kautzsch L, Mende F, Fecher GH, Winterlik J, Felser C. Are AuPd TM ( T = Sc, Y and M = Al, Ga, In), Heusler Compounds Superconductors without Inversion Symmetry? Materials (Basel) 2019; 12:ma12162580. [PMID: 31412638 PMCID: PMC6719038 DOI: 10.3390/ma12162580] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 11/16/2022]
Abstract
Heusler compounds with 2:1:1 stoichiometry either have a centrosymmetric Cu2MnAl structure or an Li2AgSb structure without a centre of inversion. The centrosymmetry is always lost in quaternary Heusler compounds with 1:1:1:1 stoichiometry and LiMgPdSn structure. This presents the possibility of realizing non-centrosymmetric superconductors in the family of Heusler compounds. The objective of this study is to search for and investigate such quaternary derivatives of Heusler compounds, particularly with respect to superconductivity. Several compounds were identified by carrying out calculations from first principles and superconductivity was observed in experiments conducted on AuPdScAl and AuPtScIn at the critical temperatures of 3.0 and 0.96 K, respectively. All investigated compounds had a valence electron count of 27, which is also the case in centrosymmetric Heusler superconductors.
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Affiliation(s)
- Linus Kautzsch
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Felix Mende
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Gerhard H Fecher
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
| | - Jürgen Winterlik
- Johannes Gutenberg-Universität, Institut für Analytische Chemie und Anorganische Chemie, 55122 Mainz, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
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12
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Schlitz R, Swekis P, Markou A, Reichlova H, Lammel M, Gayles J, Thomas A, Nielsch K, Felser C, Goennenwein STB. All Electrical Access to Topological Transport Features in Mn 1.8PtSn Films. Nano Lett 2019; 19:2366-2370. [PMID: 30844284 DOI: 10.1021/acs.nanolett.8b05042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The presence of nontrivial magnetic topology can give rise to nonvanishing scalar spin chirality and consequently a topological Hall or Nernst effect. In turn, topological transport signals can serve as indicators for topological spin structures. This is particularly important in thin films or nanopatterned materials where the spin structure is not readily accessible. Conventionally, the topological response is determined by combining magnetotransport data with an independent magnetometry experiment. This approach is prone to introduce measurement artifacts. In this study, we report the observation of large topological Hall and Nernst effects in micropatterned thin films of Mn1.8PtSn below the spin reorientation temperature TSR ≈ 190 K. The magnitude of the topological Hall effect ρ xyT = 8 nΩm is close to the value reported in bulk Mn2PtSn, and the topological Nernst effect S xyT = 115 nV K-1 measured in the same microstructure has a similar magnitude as reported for bulk MnGe ( S xyT ∼ 150 nV K-1), the only other material where a topological Nernst was reported. We use our data as a model system to introduce a topological quantity, which allows one to detect the presence of topological transport effects without the need for independent magnetometry data. Our approach thus enables the study of topological transport also in nanopatterned materials without detrimental magnetization related limitations.
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Affiliation(s)
- Richard Schlitz
- Institut für Festkörper- und Materialphysik , Technische Universität Dresden , 01062 Dresden , Germany
- Center for Transport and Devices of Emergent Materials , Technische Universität Dresden , 01062 Dresden , Germany
| | - Peter Swekis
- Max-Planck Institute for Chemical Physics of Solids , 01187 Dresden , Germany
| | - Anastasios Markou
- Max-Planck Institute for Chemical Physics of Solids , 01187 Dresden , Germany
| | - Helena Reichlova
- Institut für Festkörper- und Materialphysik , Technische Universität Dresden , 01062 Dresden , Germany
- Center for Transport and Devices of Emergent Materials , Technische Universität Dresden , 01062 Dresden , Germany
- Institute of Physics ASCR , v. v. i., Cukrovarnická 10 , 162 53 , Praha 6 , Czech Republic
| | - Michaela Lammel
- Center for Transport and Devices of Emergent Materials , Technische Universität Dresden , 01062 Dresden , Germany
- Institute for Metallic Materials , Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden) , 01069 Dresden , Germany
| | - Jacob Gayles
- Max-Planck Institute for Chemical Physics of Solids , 01187 Dresden , Germany
| | - Andy Thomas
- Center for Transport and Devices of Emergent Materials , Technische Universität Dresden , 01062 Dresden , Germany
- Institute for Metallic Materials , Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden) , 01069 Dresden , Germany
| | - Kornelius Nielsch
- Institute for Metallic Materials , Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden) , 01069 Dresden , Germany
- Institute of Materials Science , Technische Universität Dresden , 01062 Dresden , Germany
| | - Claudia Felser
- Max-Planck Institute for Chemical Physics of Solids , 01187 Dresden , Germany
| | - Sebastian T B Goennenwein
- Institut für Festkörper- und Materialphysik , Technische Universität Dresden , 01062 Dresden , Germany
- Center for Transport and Devices of Emergent Materials , Technische Universität Dresden , 01062 Dresden , Germany
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13
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Han Y, Wu Y, Li T, Khenata R, Yang T, Wang X. Electronic, Magnetic, Half-Metallic, and Mechanical Properties of a New Equiatomic Quaternary Heusler Compound YRhTiGe: A First-Principles Study. Materials (Basel) 2018; 11:ma11050797. [PMID: 29762525 PMCID: PMC5978174 DOI: 10.3390/ma11050797] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/01/2018] [Accepted: 05/10/2018] [Indexed: 11/16/2022]
Abstract
We apply First-principles theory to study the electronic structure as well as the magnetic and mechanical characteristics of YRhTiGe, a newly-designed Y-based quaternary equiatomic Heusler compound. This compound is half-metallic in nature with a ferromagnetic ground state. The total magnetic moment of YRhTiGe is 2 μB and it obeys the Slater-Pauling rule, Mt = Zt − 18, where Mt and Zt are the total magnetic moment and total number of valence electrons, respectively. The magnetic and half-metallic behaviors at its equilibrium and strained lattice constants have been discussed in detail. In addition, for FM-type YRhTiGe, its polycrystalline mechanical features such as Poisson’s ratio, Lame constants, Kleinman parameter and hardness, are also computed according to the well-known Voigt-Reuss-Hill approximation. We investigate the mechanical anisotropy of YRhTiGe using the directional dependences of the Young’s modulus and the shear modulus. Finally, we prove this compound is structurally and mechanically stable. This theoretical investigation provides further insight into the application of Y-based compounds as spintronic materials.
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Affiliation(s)
- Yilin Han
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Yang Wu
- School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China.
| | - Tingzhou Li
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - R Khenata
- Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 Mascara, Algeria.
| | - Tie Yang
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Xiaotian Wang
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
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Schwall M, Balke B. On the Phase Separation in n-Type Thermoelectric Half-Heusler Materials. Materials (Basel) 2018; 11:E649. [PMID: 29690633 DOI: 10.3390/ma11040649] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/18/2018] [Accepted: 04/19/2018] [Indexed: 11/17/2022]
Abstract
Half-Heusler compounds have been in focus as potential materials for thermoelectric energy conversion in the mid-temperature range, e.g., as in automotive or industrial waste heat recovery, for more than ten years now. Because of their mechanical and thermal stability, these compounds are advantageous for common thermoelectric materials such as Bi2Te3, SiGe, clathrates or filled skutterudites. A further advantage lies in the tunability of Heusler compounds, allowing one to avoid expensive and toxic elements. Half-Heusler compounds usually exhibit a high electrical conductivity σ, resulting in high power factors. The main drawback of half-Heusler compounds is their high lattice thermal conductivity. Here, we present a detailed study of the phase separation in an n-type Heusler materials system, showing that the TixZryHfzNiSn system is not a solid solution. We also show that this phase separation is key to the thermoelectric high efficiency of n-type Heusler materials. These results strongly underline the importance of phase separation as a powerful tool for designing highly efficient materials for thermoelectric applications that fulfill the industrial demands of a thermoelectric converter.
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Balke B, Wurmehl S, Fecher GH, Felser C, Kübler J. Rational design of new materials for spintronics: Co 2Fe Z ( Z=Al, Ga, Si, Ge). Sci Technol Adv Mater 2008; 9:014102. [PMID: 27877928 PMCID: PMC5099797 DOI: 10.1088/1468-6996/9/1/014102] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 03/13/2008] [Accepted: 01/29/2008] [Indexed: 05/31/2023]
Abstract
Spintronic is a multidisciplinary field and a new research area. New materials must be found for satisfying the different types of demands. The search for stable half-metallic ferromagnets and ferromagnetic semiconductors with Curie temperatures higher than room temperature is still a challenge for solid state scientists. A general understanding of how structures are related to properties is a necessary prerequisite for material design. Computational simulations are an important tool for a rational design of new materials. The new developments in this new field are reported from the point of view of material scientists. The development of magnetic Heusler compounds specifically designed as material for spintronic applications has made tremendous progress in the very recent past. Heusler compounds can be made as half-metals, showing a high spin polarization of the conduction electrons of up to 100% in magnetic tunnel junctions. High Curie temperatures were found in Co2-based Heusler compounds with values up to 1120 K in Co2FeSi. The latest results at the time of writing are a tunnelling magnet resistance (TMR) device made from the Co2FeAl0.5Si0.5 Heusler compound and working at room temperature with a (TMR) effect higher than 200%. Good interfaces and a well-ordered compound are the precondition to realize the predicted half-metallic properties. The series Co2FeAl1- x Si x is found to exhibit half-metallic ferromagnetism over a broad range, and it is shown that electron doping stabilizes the gap in the minority states for x=0.5. This might be a reason for the exceptional temperature behaviour of Co2FeAl0.5Si0.5 TMR devices. Using x-ray diffraction (XRD), it was shown conclusively that Co2FeAl crystallizes in the B2 structure whereas Co2FeSi crystallizes in the L21 structure. For the compounds Co2FeGa or Co2FeGe, with Curie temperatures expected higher than 1000 K, the standard XRD technique using laboratory sources cannot be used to easily distinguish between the two structures. For this reason, the EXAFS technique was used to elucidate the structure of these two compounds. Analysis of the data indicated that both compounds crystallize in the L21 structure which makes these two compounds suitable new candidates as materials in magnetic tunnel junctions.
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Affiliation(s)
- Benjamin Balke
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
| | - Sabine Wurmehl
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
| | - Gerhard H Fecher
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
| | - Claudia Felser
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
| | - Jürgen Kübler
- Institut für Festkörperphysik, Technische Universität Darmstadt, Germany
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