2020 Fiscal Year Annual Research Report
Experimental study of topological properties in chiral antiferromagnets
| Project/Area Number |
19J22078
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| Research Institution | The University of Tokyo |
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Principal Investigator |
IKHLAS RAHMAT MUHAMMAD 東京大学, 新領域創成科学研究科, 特別研究員(DC2)
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| Project Period (FY) |
2019-04-25 – 2022-03-31
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| Keywords | Magnetism / Antiferromagnet / Spintronic / Pressure / Anomalous Hall effect |
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| Outline of Annual Research Achievements |
1) We successfully collaborated with Dr. Clifford Hicks's group at Max Planck Institute for Chemical Physics of Solids in Dresden, Germany to develop a tunable uniaxial stress dilatometer, a device capable of measuring the thermal expansion of materials under high uniaxial stress. We utilized this device to study the phase diagram of non-collinear antiferromagnet Mn3Sn under uniaxial stress. This material undergoes a first-order transition from triangular spin structure to spin spiral structure at a temperature of around 280 K. We successfully applied uniaxial stress up to 1.5 GPa to this material and suppress the first-order transition by 50 K. Our study provides important thermodynamic information of the magnetic transition in Mn3Sn, a material which has promising applications in spintronics. In addition to that, we demonstrated a new technique to explore the phases of matter under extreme conditions.
2) We discovered that uniaxial strain can be a strong tuning parameter of anomalous Hall effect in the non-collinear antiferromagnet Mn3Sn. Spontaneous magnetization can be generated under uniaxial stress in certain types of antiferromagnets, which is a phenomenon known as piezomagnetism. However, the coupling between piezomagnetism and anomalous transport properties in antiferromagnets are experimentally unexplored. We demonstrated that piezomagnetism can mediate bi-directional switching of anomalous Hall effect in Mn3Sn. Our study uncovers an alternative way to control antiferromagnetic domains.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Currently, research is going well. We have published our collaboration work with Dr. Clifford Hicks's group at Max Planck Institute for Chemical Physics of Solids. Additionally, We have completed data collection and analysis for two additional manuscripts. One manuscript describes the chemical doping study of Mn3Sn and how the magnetic phase diagram evolves as a function of the dopant. The second manuscript describes the effect of uniaxial strain on the anomalous transport properties of Mn3Sn. For the latter manuscript, we collaborated with two theorists, Dr. Sayak Dasgupta and Prof. Oleg Tschernyshyov from Johns Hopkins University, and they successfully constructed a theory to explain the phenomena that we observed.
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| Strategy for Future Research Activity |
1) We are planning to carry out neutron scattering measurement of Mn3Sn under uniaxial strain to supplement our manuscript describing the strain effect on anomalous Hall effect, in collaboration with Dr. Clifford Hicks' group at Max Planck Institute and Prof. Colin Broholm's group at Johns Hopkin's University. However, the ongoing coronavirus pandemic makes it difficult to arrange beam time and coordinate the experiment. So, as an alternative plan, we will split the neutron scattering experiment result and the transport result into two separate papers.
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