Ling Yechao, Hu Yong, Wang Haobo, Niu Ben, Chen Jiawei, Liu Ruobai, Yuan Yuan, Wang Guangyu, Wu Di, Xu Mingxiang, Han Zhida, Du Jun, Xu Qingyu
School of Physics, Southeast University, Nanjing 211189, China.
Department of Physics, College of Sciences, Northeastern University, Shenyang 110819, China.
ACS Appl Mater Interfaces. 2021 May 26;13(20):24285-24294. doi: 10.1021/acsami.1c03701. Epub 2021 May 14.
The practical applications for the distinctive functions of metamagnetic Heusler alloys, such as magnetic shape memory effect, various caloric effects, etc., strongly depend on the phase transition temperatures. Here, flexible Heusler alloy Ni-Mn-Sn films have been deposited on mica substrates by pulsed laser deposition with a Ti buffer layer. Clear ferromagnetic (FM) transition followed by the martensitic transformation at around room temperature and exchange bias (EB) with a blocking temperature of 70 K are observed. Under the application of both tensile and compressive strains by bending the mica substrates, all the characteristic temperatures of Ni-Mn-Sn films, including the FM transition temperature, martensitic transformation temperature, and blocking temperature of EB, are significantly increased by about 10 K. Furthermore, EB field and coercivity are both strongly strengthened, which is mainly caused by the simultaneous enhancement of FM and anti-FM Mn-Mn coupling because of their shortened separations by strain and verified by the Monte Carlo simulation results. The strain controlling for structural and magnetic properties provides efficient manipulation for Heusler alloy-based magnetic devices.
变磁性赫斯勒合金独特功能（如磁形状记忆效应、各种热效应等）的实际应用在很大程度上取决于相变温度。在此，通过脉冲激光沉积法在云母衬底上沉积了带有钛缓冲层的柔性赫斯勒合金Ni-Mn-Sn薄膜。观察到在室温附近有明显的铁磁（FM）转变，随后是马氏体转变，并且存在阻塞温度为70 K的交换偏置（EB）。通过弯曲云母衬底施加拉伸和压缩应变时，Ni-Mn-Sn薄膜的所有特征温度，包括FM转变温度、马氏体转变温度和EB的阻塞温度，都显著提高了约10 K。此外，EB场和矫顽力都得到了显著增强，这主要是由于应变导致FM和反FM Mn-Mn耦合间距缩短，从而使它们同时增强所致，蒙特卡罗模拟结果也证实了这一点。对结构和磁性特性的应变控制为基于赫斯勒合金的磁性器件提供了有效的操控方法。
