Unusual angular dependent magnetoresistance in single-crystalline Co/Pt bilayers

摘要

The magnetoresistance (MR) of the single-crystalline Co/Pt(111) bilayers was studied systematically as a function of Co or Pt thickness at room temperature. For Co thickness d_(Co) ＜ 6 nm, the resistances with in-plane magnetization M parallel (R_‖) and transverse (R_⊥) to current and with a perpendicular M normal (R-p) to film show the unconventional behavior of R_p ＞ R_‖ ＞ R_⊥. This MR behavior can be attributed to the combination effect of spin Hall MR with R_p ≈ R_‖ ＞ R_⊥ and the geometrical size effect. In addition, the angular dependent magnetoresistance behavior of the (111)-oriented Co/Pt bilayer shows striking difference with that of the (001)-oriented Co/Pt bilayer.