Presentation Information
[15p-PB1-50]Magnetic Anisotropy in Co hBN Heterostructures Under Biaxial Strain and Layer Thickness Variation: A First Principles Study
〇Dian Putri Hastuti1, Yukie Kitaoka1, Hiroshi Imamura1 (1.AIST)
Keywords:
2D heterostructure,PMA,strain,easy cone
MA is a key property of magnetic materials that governs the preferred magnetization direction and underpins the performance of spintronic devices such as MRAM. The anisotropy energy is usually expressed in terms of first- and second-order constants K1 and K2 while K1 sets the magnetic anisotropy direction, the K2 can stabilize more complex states such as “easy-cone” configuration, and precise control of these constants is essential for optimizing device performance, particularly in STT-MRAM. 2D materials and their interfaces with ferromagnets, such as Co/h-BN, offer promising routes to engineer anisotropy via strain, which also gives rise to phenomena such as PMA [1], as well as through layer-thickness modification that influences the easy-cone state [2]. Previous studies have shown that interfacial engineering and small applied strain can induce and enhance PMA, yet the strain dependency of K1 and K2 and the emergence of easy cone states in minimal stack and modest biaxial strain has not yet been thoroughly explored. In this study, we theoretically examine the magnetic anisotropy of Co/h-BN heterostructures using first-principles calculations based on the FLAPW method. We first analyze the dependence of the MAE on the Co layer thickness, as shown in Fig. 1. A monolayer Co/h-BN heterostructure exhibits PMA driven by Co–N hybridization, whereas multilayer systems display in-plane anisotropy. Further investigation were done by applying biaxial strain to the bilayer Co (2LCo) heterostructure. Under biaxial strain up to ±4%, we observe substantial variations in the anisotropy constants (K1 and K2), resulting in magnetic phase changes from in-plane anisotropy to the easy-cone state and, ultimately, to PMA under compressive, unstrained, and tensile conditions, respectively [Fig. 2]. The PMA is originated from reduced interlayer distance which results in stronger hybridization.