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Xu X, Hao Y, Peng S, Zhang Q, Ni D, Yang C, Dai X, Cao H, Cava RJ. Large off-diagonal magnetoelectricity in a triangular Co 2+-based collinear antiferromagnet. Nat Commun 2023; 14:8034. [PMID: 38052828 DOI: 10.1038/s41467-023-43858-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 11/22/2023] [Indexed: 12/07/2023] Open
Abstract
Magnetic toroidicity is an uncommon type of magnetic structure in solid-state materials. Here, we experimentally demonstrate that collinear spins in a material with R-3 lattice symmetry can host a significant magnetic toroidicity, even parallel to the ordered spins. Taking advantage of a single crystal sample of CoTe6O13 with an R-3 space group and a Co2+ triangular sublattice, temperature-dependent magnetic, thermodynamic, and neutron diffraction results reveal A-type antiferromagnetic order below 19.5 K, with magnetic point group -3' and k = (0,0,0). Our symmetry analysis suggests that the missing mirror symmetry in the lattice could lead to the local spin canting for a toroidal moment along the c axis. Experimentally, we observe a large off-diagonal magnetoelectric coefficient of 41.2 ps/m that evidences the magnetic toroidicity. In addition, the paramagnetic state exhibits a large effective moment per Co2+, indicating that the magnetic moment in CoTe6O13 has a significant orbital contribution. CoTe6O13 embodies an excellent opportunity for the study of next-generation functional magnetoelectric materials.
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Affiliation(s)
- Xianghan Xu
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
| | - Yiqing Hao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Shiyu Peng
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Qiang Zhang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Danrui Ni
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Chen Yang
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Xi Dai
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Huibo Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
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Zhang Q, Tian W, Nepal R, Huq A, Nagler S, DiTusa JF, Jin R. Polyhedral Distortions and Unusual Magnetic Order in Spinel FeMn 2O 4. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:2330-2341. [PMID: 38616973 PMCID: PMC11008780 DOI: 10.1021/acs.chemmater.2c03182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/28/2023] [Indexed: 04/16/2024]
Abstract
Spinel compounds AB2X4 consist of both tetrahedral (AX4) and octahedral (BX6) environments with the former forming a diamond lattice and the latter a geometrically frustrated pyrochlore lattice. Exploring the fascinating physical properties and their correlations with structural features is critical in understanding these materials. FeMn2O4 has been reported to exhibit one structural transition and two successive magnetic transitions. Here, we report the polyhedral distortions and their correlations to the structural and two magnetic transitions in FeMn2O4 by employing the high-resolution neutron powder diffraction. The cation distribution is found to be (Mn0.92+Fe0.13+)A(Mn3+Fe0.93+Mn0.12+)BO4. While large trigonal distortion is found even in the high-temperature cubic phase, the first-order cubic-tetragonal structural transition associated with the elongation of both tetrahedra and octahedra with shared oxygen atoms along the c axis occurs at TS ≈ 750 K, driven by the Jahn-Teller effect of the orbital active B-site Mn3+ cation. Strong magnetoelastic coupling is unveiled at TN1 ≈ 400 K as manifested by the appearance of Néel-type collinear ferrimagnetic order, an anomaly in both tetrahedral and octahedral distortions, as well as an anomalous decrease of the lattice constants c and a weak anomaly of a. Upon cooling to TN2 ≈ 65 K, it evolves to a noncollinear ferrimagnetic order accompanied by the different moments at the split magnetic sites B1 and B2. Only one-half of the B-site Mn3+/Fe3+ spins, i.e., the B2-site spins in the pyrochlore lattice, are canted, which is a unique magnetic order among spinels. The canting angle between A-site and B2-site moments is ∼25°, but the B1-site moment stays antiparallel to the A-site moment even at 10 K. This noncollinear order is accompanied by a modification of the O-B-O bond angles in the octahedra without significant change in lattice constants or tetrahedral/octahedral distortion parameters, indicating a distinct magnetoelastic coupling. We demonstrate distinct roles of the A-site and B-site magnetic cations in the structural and magnetic properties of FeMn2O4. Our study indicates that FeMn2O4 is a wonderful platform to unveil interesting magnetic order and to investigate their correlations with polyhedral distortions and lattice.
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Affiliation(s)
- Qiang Zhang
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Wei Tian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Roshan Nepal
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Ashfia Huq
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Stephen Nagler
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - J F DiTusa
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Rongying Jin
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, United States
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Shen Z, Zhu XD, Ullah RR, Klavins P, Taufour V. Anomalous depinning of magnetic domain walls within the ferromagnetic phase of the Weyl semimetal Co 3Sn 2S 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 35:045802. [PMID: 36541539 DOI: 10.1088/1361-648x/aca57b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
We report bulk magnetization measurements and spatially resolved measurements of magnetic domains inCo3Sn2S2single crystals. The results indicate that a previously reported magnetic anomaly around 130 K is due to an anomalous domain wall depinning upon cooling. Our measurements also reveal a hysteresis between field-cooled-cooling and field-cooled-warming magnetization curves acquired under a constant magnetic field below 300 Oe. This observation rules out the possibility that the anomaly stems from a second-order phase transition. Our results further suggest that changes in the shape of hysteresis loops from 5 to 170 K are caused by an unusual temperature-dependent domain nucleation field that changes sign around 130 K. The Kerr rotation images of the magnetic domains confirm that the domain walls depin between 120 and 140 K.
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Affiliation(s)
- Zihao Shen
- Department of Physics and Astronomy, University of California, Davis, CA 95616, United States of America
| | - X D Zhu
- Department of Physics and Astronomy, University of California, Davis, CA 95616, United States of America
- Department of Optical Sciences and Engineering, Fudan University, Shanghai 200045, People's Republic of China
| | - Rahim R Ullah
- Department of Physics and Astronomy, University of California, Davis, CA 95616, United States of America
| | - Peter Klavins
- Department of Physics and Astronomy, University of California, Davis, CA 95616, United States of America
| | - Valentin Taufour
- Department of Physics and Astronomy, University of California, Davis, CA 95616, United States of America
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