Abrupt transition from ferromagnetic to antiferromagnetic of interfacial exchange in perpendicularly magnetized L1(0)-MnGa/FeCo tuned by Fermi level position

Q L Ma; S Mizukami; T Kubota; X M Zhang; Y Ando; T Miyazaki

doi:10.1103/PhysRevLett.112.157202

Abrupt transition from ferromagnetic to antiferromagnetic of interfacial exchange in perpendicularly magnetized L1(0)-MnGa/FeCo tuned by Fermi level position

Phys Rev Lett. 2014 Apr 18;112(15):157202. doi: 10.1103/PhysRevLett.112.157202. Epub 2014 Apr 18.

Authors

Q L Ma¹, S Mizukami¹, T Kubota¹, X M Zhang¹, Y Ando², T Miyazaki¹

Affiliations

¹ WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, 980-8577 Sendai, Japan.
² Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05, Aoba-yama, 980-8579 Sendai, Japan.

PMID: 24785068
DOI: 10.1103/PhysRevLett.112.157202

Abstract

An abrupt transition of the interfacial exchange coupling from ferromagnetic to antiferromagnetic was observed in the interface of perpendicularly magnetized L10-MnGa/Fe1-xCox epitaxial bilayers when x was around 25%. By considering the special band structure of the MnGa alloy, we present a model explaining this transition by the spin-polarization reversal of Fe1-xCox alloys due to the rise of the Fermi level as the Co content increases. The effect of interfacial exchange coupling on the coercive force (Hc) and the spin-dependent tunneling effect in perpendicular magnetic tunnel junctions (pMTJs) based on the coupled composite were also studied. Changes from the normal spin valve to inverted magnetoresistance loops corresponding to the coupling transition were observed in pMTJs with MnGa/Fe1-xCox as an electrode.