Atomic-to-Mesoscale Twinning Effects and Strain-Driven Magnetic States in an Anisotropic 2D Ferromagnet FePd<sub>2</sub>Te<sub>2</sub>
Shuo Mi, Manyu Wang, Bingxian Shi, Songyang Li, Xiaoxiao Pei, Yanyan Geng, Sheng Meng, Rui Xu, Li Huang, Wei Ji, Fei Pang, Peng Cheng, Jianfeng Guo, Zhihai Cheng
Abstract
Strain engineering offers a compelling route to modulate magnetism in two-dimensional (2D) materials, yet most approaches rely on externally applied strain. An in-plane anisotropic 2D-layered ferromagnet FePd 2 Te 2 provides a suitable platform to study intrinsic strain-magnetism coupling due to its twinning domains. Here, we report spatially modulated internal compressive/tensile(C/T) strain regions in FePd 2 Te 2 and their strong impact on local magnetic properties in real space by using atomic/magnetic force microscopy (AFM/MFM) combined with scanning tunneling microscopy (STM). Field- and strain-dependent spin transformations reveal the modulation of its intrinsic C/T regions. Notably, C regions retain intact Fe zigzag chains and exhibit larger, abruptly switching magnetic moments, while T regions display fragmented chains with reduced, gradually rotating spins. The intrinsic strain-induced intact ferromagnetic (FM), field-induced polarized-FM states, and their transitions are comparatively discussed during magnetic measurements. Temperature- and field-dependent evolution are further investigated in the FM and paramagnetic (PM) states and summarized to obtain an H-T phase diagram of FePd 2 Te 2 . Our work provides key results for understanding real-space tunable magnetic states through internal structural heterogeneity and suggests potential strategies for manipulating intrinsic strain-engineered magnetic devices.