Enhancement of Perpendicular Exchange Bias by Introducing Twin Boundary in Pt/Co/α-Cr₂O₃/α-V₂O₃ Epitaxial Film

抄録

Perpendicular exchange anisotropy at the Co/α-Cr₂O₃ interface was investigated using the two types of films: the film with the single crystalline α-Cr₂O₃ and that with the twinned α-Cr₂O₃. Exchange anisotropy energy density J_K of the film with the single crystalline α-Cr₂O₃ was ∼0.09 erg/cm² whereas J_K of the film with the twinned α-Cr₂O₃ was ∼0.43 erg/cm², more than 4-times enhancement. We discussed the mechanism of the enhancement of J_K based on the exchange coupling at the twin boundary and that the spin frustration at the twin boundary can be the origin of the enhancement of J_K.

Fig. 4 Temperature dependence of exchange bias field H_EX (red circle, left axis), J_K (red circle, right axis) and coercivity H_C (blue circle, left axis) for the films with (a) without and (b) with the Pt buffer layer, respectively. On the right axis, the exchange magnetic anisotropy energy density J_K, calculated using H_EX was shown.