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Ishtiyak M, Watts SR, Thipe B, Womack F, Adams P, Bai X, Young DP, Bobev S, Baranets S. Advancing Heteroanionicity in Zintl Phases: Crystal Structures, Thermoelectric and Magnetic Properties of Two Quaternary Semiconducting Arsenide Oxides, Eu 8Zn 2As 6O and Eu 14Zn 5As 12O. Inorg Chem 2024. [PMID: 38904454 DOI: 10.1021/acs.inorgchem.4c01580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Two novel quaternary oxyarsenides, Eu8Zn2As6O and Eu14Zn5As12O, were synthesized through metal flux reactions, and their crystal structures were established by single-crystal X-ray diffraction methods. Eu8Zn2As6O crystallizes in the orthorhombic space group Pbca, featuring polyanionic ribbons composed of corner-shared triangular [ZnAs3] units, running along the [100] direction. The structure of Eu14Zn5As12O crystallizes in the monoclinic space group P2/m and its anionic substructure can be described as an infinite "ribbonlike" chain comprised of [ZnAs3] trigonal-planar units, although the structural complexity here is greater and also amplified by disorder on multiple crystallographic positions. In both structures, the O2- anion occupies an octahedral void with six neighboring Eu2+ cations. Formal electron counting, electronic structure calculations, and transport properties reveal the charge-balanced semiconducting nature of these heteroanionic Zintl phases. High-temperature thermoelectric transport properties measurements on Eu14Zn5As12O reveal relatively high resistivity (ρ500K = 8 Ω·cm) and Seebeck coefficient values (S500K = 220 μV K-1), along with a low concentration and mobility of holes as the dominant charge-carriers (n500K = 8.0 × 1017 cm-3, μ500K = 6.4 cm2/V s). Magnetic studies indicate the presence of divalent Eu2+ species in Eu14Zn5As12O and complex magnetic ordering, with two transitions observed at T1 = 21.6 K and T2 = 9 K.
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Affiliation(s)
- Mohd Ishtiyak
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Spencer R Watts
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Bhushan Thipe
- Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Frank Womack
- Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Philip Adams
- Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Xiaojian Bai
- Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - David P Young
- Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Svilen Bobev
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sviatoslav Baranets
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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2
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Wildman EJ, Lawrence GB, Walsh A, Morita K, Simpson S, Ritter C, Stenning GBG, Arevalo-Lopez AM, Mclaughlin AC. Observation of an exotic insulator to insulator transition upon electron doping the Mott insulator CeMnAsO. Nat Commun 2023; 14:7037. [PMID: 37923745 PMCID: PMC10624918 DOI: 10.1038/s41467-023-42858-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/17/2023] [Indexed: 11/06/2023] Open
Abstract
A promising route to discover exotic electronic states in correlated electron systems is to vary the hole or electron doping away from a Mott insulating state. Important examples include quantum criticality and high-temperature superconductivity in cuprates. Here, we report the surprising discovery of a quantum insulating state upon electron doping the Mott insulator CeMnAsO, which emerges below a distinct critical transition temperature, TII. The insulator-insulator transition is accompanied by a significant reduction in electron mobility as well as a colossal Seebeck effect and slow dynamics due to decoupling of the electrons from the lattice phonons. The origin of the transition is tentatively interpreted in terms of many-body localization, which has not been observed previously in a solid-state material.
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Affiliation(s)
- E J Wildman
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, UK
| | - G B Lawrence
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, UK
| | - A Walsh
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
| | - K Morita
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
| | - S Simpson
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, UK
| | - C Ritter
- Institut Laue Langevin, 71 Avenue des Martyrs, BP 156, F-38042, Grenoble, Cedex 9, France
| | - G B G Stenning
- ISIS Experimental Operations Division, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0QX, UK
| | - A M Arevalo-Lopez
- Université de Lille, CNRS, Centrale Lille, ENSCL, Université d'Artois, UMR 8181-UCCS-Unité de Catalyse et Chimie du Solide, F-59000, Lille, France
| | - A C Mclaughlin
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, UK.
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Deng J, Pan J, Zhang YF, Du S. Database Construction of Two-Dimensional Charged Building Blocks for Functional-Oriented Material Design. NANO LETTERS 2023; 23:4634-4641. [PMID: 37146245 DOI: 10.1021/acs.nanolett.3c01237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Databases for charge-neutral two-dimensional (2D) building blocks (BBs), i.e., 2D materials, have been built for years due to their applications in nanoelectronics. Though lots of solids are constructed from charged 2DBBs, a database for them is still missing. Here, we identify 1028 charged 2DBBs from Materials Project database using a topological-scaling algorithm. These BBs host versatile functionalities including superconductivity, magnetism, and topological properties. We construct layered materials by assembling these BBs considering valence state and lattice mismatch and predict 353 stable layered materials by high-throughput density functional theory calculations. These materials can not only inherit their functionalities but also show enhanced/emergent properties compared with their parent materials: CaAlSiF displays superconducting transition temperature higher than NaAlSi; Na2CuIO6 shows bipolar ferromagnetic semiconductivity and anomalous valley Hall effect that are absent in KCuIO6; LaRhGeO possesses nontrivial band topology. This database expands the design space of functional materials for fundamental research and potential applications.
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Affiliation(s)
- Jun Deng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinbo Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yan-Fang Zhang
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shixuan Du
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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Alam M, Chatterjee S. B-site order/disorder in A 2BB'O 6and its correlation with their magnetic property. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:223001. [PMID: 36888997 DOI: 10.1088/1361-648x/acc295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
The disorder in any system affects their physical behavior. In this scenario, we report the possibility of disorder in A2BB'O6oxides and their effect on different magnetic properties. These systems show anti-site disorder by interchanging B and B' elements from their ordered position and giving rise to an anti-phase boundary. The presence of disorder leads to a reduction in saturationMand magnetic transition temperature. The disorder prevents the system from sharp magnetic transition which originates short-range clustered phase (or Griffiths phase) in the paramagnetic region just above the long-range magnetic transition temperature. Further, we report that the presence of anti-site disorder and anti-phase boundary in A2BB'O6oxides give different interesting magnetic phases like metamagnetic transition, spin-glass, exchange bias, magnetocaloric effect, magnetodielectric, magnetoresistance, spin-phonon coupling, etc.
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Affiliation(s)
- Mohd Alam
- Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Sandip Chatterjee
- Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
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Arah B, Ritter C, Stenning GBG, Mclaughlin AC. Magnetic Phase Separation in the Oxypnictide Sr 2Cr 1.85Mn 1.15As 2O 2. Inorg Chem 2022; 61:12518-12525. [PMID: 35926167 PMCID: PMC9387525 DOI: 10.1021/acs.inorgchem.2c00885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Layered Sr2M3As2O2-type
oxypnictides are composed of tetrahedral M2Pn2 and square planar MO2 layers, the building blocks of
iron-based and cuprate superconductors. To further expand our understanding
of the chemical and magnetic properties of the Sr2Cr3–xMnxAs2O2 solid solution, Sr2Cr2MnAs2O2 has been synthesized. The compound
crystallizes in the I4/mmm tetragonal
space group with a refined stoichiometry of Sr2Cr1.85Mn1.15As2O2. The M(2) site within
the M2Pn2 slab is occupied by 42.7% Cr and 57.3%
Mn, and the magnetic moments order antiferromagnetically below TN(M2) = 540 K with a C-type antiferromagnetic structure. The
M(1) site within the MO2 layers is fully occupied by Cr,
and antiferromagnetic order is observed below TN(M1) =
200 K. Along c, there are two possible interplanar
arrangements: ferromagnetic with the (1/2, 1/2, 0) propagation vector
and antiferromagnetic with the (1/2, 1/2, 1/2) propagation vector.
Magnetic phase separation arises so that both propagation vectors
are observed below 200 K. Such magnetic phase separation has not been
previously observed in Sr2M3As2O2 phases (M = Cr, Mn) and shows that there are several competing
magnetic structures present in these compounds. Layered Sr2M3As2O2-type oxypnictides are composed of tetrahedral
M2Pn2 and square planar MO2 layers,
the building blocks
of iron-based and cuprate superconductors. Sr2Cr1.85Mn1.15As2O2 is antiferromagnetic
and semiconducting. Surprisingly magnetic phase segregation is observed
in the oxypnictide Sr2Cr1.85Mn1.15As2O2 because of competing magnetic exchange
interactions along c.
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Affiliation(s)
- Bor Arah
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
| | - Clemens Ritter
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Gavin B G Stenning
- ISIS, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX, U. K
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Lawrence GB, Wildman EJ, Stenning GBG, Ritter C, Fauth F, Mclaughlin AC. Electronic and Magnetic Properties of Cation Ordered Sr 2Mn 2.23Cr 0.77As 2O 2. Inorg Chem 2020; 59:7553-7560. [PMID: 32432871 DOI: 10.1021/acs.inorgchem.0c00447] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several different mechanisms of magnetoresistance (MR) have been observed in 1111 LnMnAsO1-xFx oxypnictides (Ln = lanthanide) as a result of magnetic coupling between the Mn and Ln. Such phases also exhibit interesting magnetic phase transitions upon cooling. Sr2Mn2CrAs2O2 has been synthesized to investigate if it is possible to observe MR and/or magnetic phase transitions as a result of magnetic coupling between the Mn and Cr. Sr2Mn2CrAs2O2 crystallizes in the tetragonal space group I4/mmm containing alternating MO22- and M'2As22- layers, and neutron diffraction results demonstrate that the actual stoichiometry is Sr2Mn2.23Cr0.77As2O2. Cation order is present between Mn and Cr, with Cr predominantly occupying the square planar MO22- site. Below 410 K, the magnetic moments of the Mn/Cr ions in the M'2As22- sublattice exhibit G-type antiferromagnetic order. The Mn/Cr moments within the MO22- layer order below 167 K with a K2NiF4-type antiferromagnetic structure that simultaneously induces a spin flip of the magnetic moments in the M'2As22- layers from a G-type to a C-type antiferromagnetic arrangement. The results demonstrate that the superexchange interactions are finely balanced in Sr2Mn2.23Cr0.77As2O2. Sr2Mn2.23Cr0.77As2O2 is semiconducting, and there is no evidence of MR.
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Affiliation(s)
- Gaynor B Lawrence
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland.,Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Eve J Wildman
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
| | - Gavin B G Stenning
- ISIS, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K
| | - Clemens Ritter
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Francois Fauth
- CELLS-ALBA Synchrotron, E-08290 Cerdanyola del Vallès, Barcelona, Spain
| | - Abbie C Mclaughlin
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
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Wildman EJ, McCombie KS, Stenning GBG, Mclaughlin AC. The suppression of CMR in Nd(Mn 1-xCo x)AsO 0.95F 0.05. Dalton Trans 2018; 47:14726-14733. [PMID: 30280742 DOI: 10.1039/c8dt03071e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The colossal magnetoresistance (CMR) observed in the oxypnictide NdMnAsO1-xFx has been further investigated. The magnetotransport is dominated by magnetopolarons. Magnetoresistance measurements of the series Nd(Mn1-xCox)AsO0.95F0.05 show that doping with cobalt on the manganese site pins the magnetopolarons and suppresses the CMR, which is completely destroyed by x = 0.047. The chemical doping results in non-stoichiometric samples, with both As and O vacancies. The relationship between the non-stoichiometry, magnetic order, electron doping and CMR is explored. The Nd antiferromagnetic transition and simultaneous reorientation of the Mn spins into the basal plane at 23 K (TSR) is not effected by Co doping. However, there is a significant decrease in TN(Mn) as the antiferromagnetic transition is suppressed from 360 K to 300 K as x increases from 0-0.047. The manganese moment at 10 K is also reduced from 3.86(2)μB to 3.21(2)μB over the same doping range. This reduction in the in-plane Mn moment decreases the electron-electron correlations below TSR and acts to further diminish the magnetoresistance.
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Affiliation(s)
- E J Wildman
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland, UK.
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8
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Gamon J, Haller S, Guilmeau E, Maignan A, Le Mercier T, Barboux P. Mechanochemical synthesis of iodine-substituted BiCuOS. J SOLID STATE CHEM 2018. [DOI: 10.1016/j.jssc.2018.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ishida J, Iimura S, Hosono H. Structural Series in the Ternary A–Mn–As System (A = Alkali Metal): Double-Layer-Type CsMn4As3 and RbMn4As3 and Tunnel-Type KMn4As3. Inorg Chem 2018; 57:4997-5003. [DOI: 10.1021/acs.inorgchem.8b00018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Plokhikh IV, Charkin DO, Verchenko VY, Kuznetsov AN, Kazakov SM, Tsirlin AA, Shevelkov AV. Structural and Thermodynamic Stability of the "1111" Structure Type: A Case Study of the EuFZnPn Series. Inorg Chem 2016; 55:12409-12418. [PMID: 27934435 DOI: 10.1021/acs.inorgchem.6b02297] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two new compounds with the LaOAgS structure, EuFZnAs (1) and EuFZnSb (2), were obtained via solid state reaction. Both compounds are tetragonal (P4/nmm) with the cell parameters a = 4.1000(1) Å and c = 9.0811(1) Å for 1 and a = 4.2852(1)Å and c = 9.4238(1)Å for 2. The absence of their phosphide analog can be explained based on crystal chemical considerations as well as on quantum-chemical estimates of their thermodynamic stability with respect to EuF2 and EuZn2Pn2. The magnetic response of 1 and 2 is ascribed to the presence of Eu2+ ions. Both compounds are paramagnetic down to low temperatures, where they order antiferromagnetically at ∼5 K and ∼3 K, respectively. They are narrow-gap semiconductors, and EuFZnSb demonstrates a relatively high value of the Seebeck coefficient.
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Affiliation(s)
- Igor V Plokhikh
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Dmitri O Charkin
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics , 12618 Tallinn, Estonia
| | - Alexey N Kuznetsov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia.,N.S. Kurnakov Institute of General and Inorganic Chemistry RAS , 119991 Moscow, Russia
| | - Sergey M Kazakov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Correlations and Magnetism, Institute of Physics, University of Augsburg , 86135 Augsburg, Germany
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
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Wildman EJ, Mclaughlin AC. A Variable Temperature Synchrotron X-ray Diffraction Study of Colossal Magnetoresistant NdMnAsO0.95F0.05. Sci Rep 2016; 6:20705. [PMID: 26875693 PMCID: PMC4753427 DOI: 10.1038/srep20705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/11/2016] [Indexed: 11/22/2022] Open
Abstract
The recent discovery of high temperature superconductivity in Fe arsenides has invigorated research into transition metal pnictides. Colossal magnetoresistance (CMR) has recently been reported for NdMnAsO1-xFx for x = 0.05–0.08, with a maximum magnetoresistance achieved at low temperature (MR9T(3 K)) = −95%). This appears to be a novel mechanism of CMR, which is as a result of a second order phase transition in field from an insulating antiferromagnet to a semiconducting paramagnet. Here we report a variable temperature synchrotron X-ray powder diffraction study of the CMR oxypnictide NdMnAsO0.95F0.05 between 4 K–290 K. An excellent fit to the tetragonal unit cell with space group P4/nmm is obtained over the entire temperature range, with no change in crystal structure detected down to 4 K. A coupling of the lattice and magnetic order is observed, where subtle discontinuities in the temperature variation of a and the c/a ratio are apparent as the Nd spins order antiferromagnetically and the Mn moments reorient into the basal plane at TSR. The results suggest that very small changes in lattice parameters effect the coupling between lattice, electronic and magnetic degrees of freedom.
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Affiliation(s)
- E J Wildman
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland
| | - A C Mclaughlin
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland
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Roychowdhury S, Ghara S, Guin SN, Sundaresan A, Biswas K. Large linear magnetoresistance in topological crystalline insulator Pb0.6Sn0.4Te. J SOLID STATE CHEM 2016. [DOI: 10.1016/j.jssc.2015.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wildman EJ, Tucker MG, Mclaughlin AC. A high pressure neutron study of colossal magnetoresistant NdMnAsO(0.95)F(0.05). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:116001. [PMID: 25721358 DOI: 10.1088/0953-8984/27/11/116001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A high pressure neutron diffraction study of the oxypnictide NdMnAsO0.95F0.05 has been performed at temperatures of 290-383 K and pressures up to 8.59 GPa. The results demonstrate that the antiferromagnetic order of the Mn spins is robust to pressures of up to 8.59 GPa. TN is enhanced from 360 to 383 K upon applying an external pressure of 4.97 GPa, a rate of 4.63 K GPa(-1). NdMnAsO0.95F0.05 is shown to violate Bloch's rule which would suggest that NdMnAsO0.95F0.05 is on the verge of a localized to itinerant transition. There is no evidence of a structural transition but applied pressure tends to result in more regular As-Mn-As and Nd-O-Nd tetrahedra. The unit cell is significantly more compressible along the c-axis than the a-axis, as the interlayer coupling is weaker than the intrinsic bonds contained within NdO and MnAs slabs.
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Affiliation(s)
- E J Wildman
- The Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland, UK
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Wildman EJ, Sher F, Mclaughlin AC. Absence of colossal magnetoresistance in the oxypnictide PrMnAsO0.95F0.05. Inorg Chem 2015; 54:2536-42. [PMID: 25713929 DOI: 10.1021/ic502445t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recently reported a new mechanism of colossal magnetoresistance (CMR) in electron doped manganese oxypnictides NdMnAsO1-xFx. Magnetoresistances of up to -95% at 3 K have been observed. Here we show that upon replacing Nd for Pr, the CMR is surprisingly no longer present. Instead a sizable negative magnetoresistance is observed for PrMnAsO0.95F0.05 below 35 K (MR7T (12 K) = -13.4% for PrMnAsO0.95F0.05). A detailed neutron and synchrotron X-ray diffraction study of PrMnAsO0.95F0.05 has been performed, which shows that a structural transition, Ts, occurs at 35 K from tetragonal P4/nmm to orthorhombic Pmmn symmetry. The structural transition is driven by the Pr 4f electrons degrees of freedom. The sizable -MR observed below the transition most likely arises due to a reduction in magnetic and/or multipolar scattering upon application of a magnetic field.
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Affiliation(s)
- Eve J Wildman
- The Chemistry Department, University of Aberdeen , Meston Walk, Aberdeen AB24 3UE, Scotland
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15
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Gu H, Zhang X, Wei H, Huang Y, Wei S, Guo Z. An overview of the magnetoresistance phenomenon in molecular systems. Chem Soc Rev 2013; 42:5907-43. [DOI: 10.1039/c3cs60074b] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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