Magneto-structural instability in the ferromagnetic shape memory alloy of composition Ni$_2$Mn$_{1.4}$Sn$_{0.6}$ is investigated by transport and magnetic measurements. Large negative magnetoresistance is observed around the martensitic transition temperature (90-210 K). Both magnetization and magnetoresistance data indicate that upon the application of an external magnetic field at a constant temperature, the sample attains a field-induced arrested state which persists even when the field is withdrawn. We observe an intriguing behavior of the arrested state that it can remember the last highest field it has experienced. The field-induced structural transition plays the key role for the observed anomaly and the observed irreversibility can be accounted by the Landau-type free energy model for the first order phase transition.
Thermally quenched metastability in metal-insulator transitions via elemental substitution
The University of Tokyo（东京大学）；National Institute of Advanced Industrial Science and Technology（产业技术综合研究所）；Graduate School of Engineering and Science, Shibaura Institute of Technology（芝浦工业大学研究生院理工学研究科）；RIKEN Center for Emergent Matter Science（理化学研究所新兴物质科学研究中心）；University of Tsukuba（筑波大学）；Institute of Science Tokyo（东京科学大学）；National Institute for Materials Science（国立材料研究所）
Room-temperature multistage metastability in a moiré superstructure
Tsung-Dao Lee Institute, School of Physics and Astronomy, Shanghai Jiao Tong University（上海交大李政道理论与计算科学中心，物理与天文学院）；Massachusetts Institute of Technology（麻省理工学院）；Stanford University（斯坦福大学）；Peking University（北京大学）；Beijing Academy of Quantum Information Sciences（北京量子信息科学研究院）；Tianjin University of Technology（天津理工大学）
History dependent nucleation and growth of the martensitic phase in a magnetic shape memory alloy Ni$_{45}$Co$_{5}$Mn$_{38}$Sn$_{12}$
通过磁化强度随时间的演化，研究了记忆合金Ni $_{45}$ Co $_{5}$ Mn $_{38}$ Sn $_{12}$体系中通过磁场（H）和T空间中不同路径产生的亚稳共存相的低温（T）动力学。结果表明，这些共存相组成的一部分动力学逮捕奥氏体相和低T平衡马氏体相的剩余部分进行缓慢的弛豫低磁化（马氏体）状态，但在相同的T和H有非常不同的热磁历史依赖率。我们发现，当马氏体相的形核是在低得多的温度下通过类玻璃态的去阻止而不是相应的一级相变（在高得多的温度下通过过冷）开始时，长时间弛豫速率与非平衡相分数成比例，但对温度的依赖性很弱。这是解释的基础上的H-T路径依赖的核的临界半径的大小和随后的增长的平衡相通过运动的界面。
Evolution of a metastable phase with a magnetic phase coexistence phenomenon and its unusual sensitivity to magnetic field cycling in the alloys Tb5-xLuxSi3 (x <= 0.7)
Irreversibility of field-induced magnetostructural transition in NiCoMnSb shape memory alloy revealed by magnetization, transport and heat capacity studies
研究了磁场对Ni 45 Co 5 Mn 38 Sb 12马氏体相变的影响。我们发现该系统存在很大的场致不可逆性，正如电阻率、磁化强度和热容量数据的场依赖性所揭示的那样。在临界温度下，场致马氏体向奥氏体相的转变在任何场变化下都是不可逆的。在该温度下，任何能量波动都会以亚稳马氏体相为代价诱导平衡奥氏体相的成核和生长并被阻止。所有这三个测量完全排除了奥氏体和马氏体相共存的不可逆制度。
