题 目：Pulsed magnetic-field studies on several quantum and frustrated magnets under high pressure

报告人：Masayuki Hagiwara教授，日本大阪大学

时间：2024年11月4日（周一）上午9:30

地点：国家脉冲强磁场科学中心B206

报告摘要：

I will talk about two research subjects studied in pulsed magnetic fields (H) under high pressures (P) after brief introduction of our facilities. The first subject is two-leg ladder compounds Cu(DEP)X₂(X=Br and Cl). Both compounds possess a spin gap between a singlet ground state and an excited triplet state at zero field. The spin gap vanishes not only by H but also by P at zero field in Cu(DEP)Br₂, but the spin gap vanishes byHbut does not by P in Cu(DEP)Cl₂. The difference between these compounds under pressure is discussed by the change in exchange interactions determined by the magnetic susceptibility measurements using a proximity diode oscillator. The second subject is a triangular-lattice antiferromagnet CsCuCl₃in which CuCl₃chains run along the c axis. A field-induced quantum phase transition from umbrella to 2-1 coplanar phase forH||c axis was reported, and up-up-down (UUD) phase appeared under pressure between these two phases. We have constructedH-Pphase diagram and observed Y-coplanar phase above 1.7 GPa. The origins of these phases are discussed by the changes in exchange and anisotropy parameters under pressure, resulting from a crossover from the semi-classical to the quantum spin regime in CsCuCl₃.

报告人简介：

Masayuki Hagiwara，日本大阪大学教授、先端强磁场科学研究中心主任。1992年在大阪大学获得理学博士学位,之后在日本东芝公司、日本理化所(RIKEN)任职，2004年加入日本大阪大学先端强磁场科学中心。研究领域为低维量子自旋体系，尤其专长于Luttinger液体、Haldane自旋链以及Kagome磁阻挫体系在极低温和强磁场下的实验研究，在PRL、PRB等凝聚态物理领域期刊发表学术论文400余篇。