Hybrid magnetoresistance in the proximity of a ferromagnet

Abstract

We report a new magnetoresistance (MR) effect observed in a nominally nonmagnetic metal (Pt) thin film in contact with either a ferromagnetic insulator or a ferromagnetic metal. The resistivities with in-plane magnetic fields parallel (${\ensuremath{\rho}}_{\ensuremath{\parallel}}$) and transverse (${\ensuremath{\rho}}_{\mathrm{T}}$) to a current and a perpendicular field (${\ensuremath{\rho}}_{\ensuremath{\perp}}$) show the behavior of ${\ensuremath{\rho}}_{\ensuremath{\perp}}$ \ensuremath{\approx} ${\ensuremath{\rho}}_{\ensuremath{\parallel}}$ > ${\ensuremath{\rho}}_{\mathrm{T}}$, distinctly different from all other known MR effects, including anisotropic MR with ${\ensuremath{\rho}}_{\ensuremath{\parallel}}$ > ${\ensuremath{\rho}}_{\mathrm{T}}$ \ensuremath{\approx} ${\ensuremath{\rho}}_{\ensuremath{\perp}}$. We termed the new MR as hybrid MR, which appears in a metal in close proximity with a ferromagnet either insulating or metallic, and is associated with the induced magnetic moments at the interface.