Half-metallicity and Gilbert damping constant in Co2FexMn1−xSi Heusler alloys depending on the film composition

Abstract

Transport properties in magnetic tunnel junctions (MTJs) with Co2FexMn1−xSi (CFMS, x=0–1.0)/Al–O/Co75Fe25 structure and Gilbert damping constant in the epitaxial CFMS films were investigated. The tunnel magnetoresistance ratio is as high as 75% in MTJs with x=0.6 at room temperature. The Gilbert damping constant is minimal at x=0.4. Relations between half-metallicity and the Gilbert damping constant in CFMS films were examined, revealing that the damping constant is small in half-metallic CFMS films.