| 研究実績の概要 |
1) I have synthesized single crystals of Mn3+xSn1-x with various Mn concentration (0 < x < 0.1) by the Bridgman method, and established its magnetic phase diagram through systematic measurements of the single crystals' magnetic and transport properties. We found that the intrinsic ground state of pristine Mn3Sn is a spiral spin structure, and upon warming above T = 280 K, a first order transition to triangular structure occurs. Doping 6% of Sn site by Mn suppresses the first-order transition completely. Our study has important implication for future thin film growths of this material.
2) I visited Dr. Clifford Hicks' group at Max Planck Institute for Chemical Physics of Solids in Dresden, Germany, to construct a dilatometer device which can measure thermal expansion of materials under uniaxial pressure. We succeeded in constructing this device and tested its capability by performing uniaxial pressure experiments on Mn3Sn. We found a lattice anomaly appearing at the first order transition in this material. The anomaly is shifted by 50 K by the application of 1.5 GPa pressure along the c-axis. We found that the effect uniaxial pressure is significantly weaker than doping, which raises the question of what kinds of magnetic interactions are relevant in this system.
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