講演情報
[8p-N304-8]Perpendicular and In-plane Magnetic Anisotropy in Co/h-BN Heterostructure: a First-principles Calculation
〇Dian Putri Hastuti1, Yukie Kitaoka1, Hiroshi Imamura1 (1.AIST)
キーワード：
h-BN、spintronics、VCMA
Traditionally, PMA enhancement has relied on FM/oxide interfaces based on cubic symmetry, a strategy that has effectively boosted the stability & performance of magnetic storage systems. However, with the shift from 3D to 2D channel materials, it's important to explore tunnel barriers compatible with 2D materials that exhibit hexagonal symmetry. To develop 2D-based spintronic devices with hexagonal symmetry, the magnetic anisotropy (MA) of a FM film on a hexagonal material must be investigated. Recent studies show that Co/h-BN heterostructures can display TMR ratios ~ those of Fe/MgO structures^[1)]. Despite this potential, the study of magnetocrystalline anisotropy (MCA) & its underlying mechanisms in Co/h-BN systems remains limited. In this work, we use 1st-principles calc. (FLAPW method) to study the MA of Co/h-BN heterostructures. A buckled h-BN structure is stable & yields higher MCA energy. We analyze the dependence of MCA energy (MCAE) on Co film thickness by varying Co layers (1–5L). A PMA of 1.68 mJ/m^2 is observed for 1L Co, similar to single Fe on MgO^[2)]. An external E-field applied to monolayer Co/h-BN gives a VCMA of –175 fJ/V·m. For thicker Co films (2–5L), in-plane magnetization suggests potential use in highly sensitive B-field sensors. For such apps, smooth variation of magnetization w/ signal B-field is crucial. We computed the angular dependence of total MAE vs in-plane angle φ_m (0°–120°). The total MAE remains constant (within ±0.1 μeV), an ideal trait for sensor functionality.