| 研究実績の概要 |
1. We found a large piezomagnetic effect in an antiferromagnetic metal Mn3Sn at room temperature. In a certain class of antiferromagnets, a linear coupling between strain and magnetization is allowed and is known as “piezomagnetism”, which can be technologically relevant if the effect is large at room temperature. We found that through this piezomagnetism, a strain in the order of 0.1% can control the magnitude and sign of the Hall signal in Mn3Sn, an effect not previously seen in antiferromagnets. We collaborated with Dr. Dasgupta from UBC and Prof. Tschernyshov from Johns Hopkins University, and they were able to construct a Landau theory which can explain the piezomagnetic effect and the modulation of the AHE signal in the same framework. This work has been accepted into Nature Physics.
2. We established the magnetic phase diagram of triangular AFM Mn3Sn as a function of Mn concentration for the first time. We successfully grew Mn3+xSn1-x single crystals within the range 0.009 < x < 0.1. We found that the ground state of a pristine Mn3Sn is an incommensurate magnetic order, which is separated from the triangular antichiral phase by a first-order transition at T=280 K. Through magnetometry and transport measurements, we show that doping Mn strongly suppresses the incommensurate phase in favor of the triangular antichiral phase but leads to the appearance of a glassy ferromagnetic phase at lower temperatures. This work will be important in the development of thin film Mn3Sn, which is a material that has recently gained much attention in the spintronics community.
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