An all-Heusler design scheme for high-performance CPP-GMR read heads

Abstract

We present an all-Heusler architecture which could be used as a rational design scheme for the giant magnetoresistive (GMR) junctions. A Co 2MnSi (CMS)/Ni2NiSi (NNS)/Co2MnSi trilayer stack is chosen as the prototype of such a scheme, of which the electronic structure and magnetotransport properties are systematically investigated by using first principles approaches. Almost excellent band matching and Fermi-surface overlap between the all-Heusler electrode-spacer pair are found, indicating large interfacial spin-asymmetry and high GMR ratio. Further transport calculations confirmed the superiority of the all-Heusler architecture over the conventional Heusler/Transition-Metal(TM) structure by comparing their transmission coefficients and interfacial resistances of parallel conduction electrons. We suggest future theoretical and experimental efforts in developing high performance all-Heusler GMR junction for the read head of the next generation high-density hard disk drives (HDDs). © 2012 DSI.