A Distinct Spin Structure and Giant Baromagnetic Effect in MnNiGe Compounds with Fe-Doping
Feiran Shen, Houbo Zhou, Fengxia Hu, Jian-Tao Wang, Hui Wu, Q. Huang, Jiazheng Hao, Zibing Yu, Yihong Gao, Yuan Lin, Yangxin Wang, Cheng Zhang, Z. G. Yin, Jing Wang, Sihao Deng, Jie Chen, Lunhua He, Tianjiao Liang, Jirong Sun, Tongyun Zhao, Baogen Shen
Abstract
Spin structure of a magnetic system results from the competition of various exchange couplings. Pressure-driven spin structure evolution, through altering interatomic distance, and hence, electronic structure produces baromagnetic effect (BME), which has potential applications in sensor/actuator field. Here, we report a new spin structure(CyS-AFMb) with antiferromagnetic(AFM) nature in Fe-doped Mn0.87Fe0.13NiGe. Neutron powder diffraction (NPD) under in situ hydrostatic pressure and magnetic field was conducted to reveal the spin configuration and its instabilities. We discovered that a pressure higher than 4 kbar can induce abnormal change of Mn(Fe)–Mn(Fe) distances and transform the CyS-AFMb into a conical spiral ferromagnetic(FM) configuration(45°-CoS-FMa) with easily magnetized but shortened magnetic moment by as much as 22%. The observed BME far exceeds previous reports. Our first-principles calculations provide theoretical supports for the enhanced BME. The compressed lattice by pressure favors the 45°-CoS-FMa and significantly broadened 3d bandwidth of Mn(Fe) atoms, which leads to the shortened magnetic moment and evolution of spin structure.