Approach towards full Heusler alloy based CPP-GMR: from Ag and non-magnetic Heusler to binary intermetallic spacers

Recently, it has been demonstrated that GMR response can be significantly enhanced by incorporating high spin polarization ferromagnetic (FM) full Heulser alloy into spin valve nano-structures. Experimental results for two types of non-magnetic spacers (i) elemental metal [1] and (ii) non-magnetic Heusler alloy spacers [2] deserve careful comparison. More practical (110) textured combination of Co$_{2}$MnGe (CMG) and non-magnetic Heusler alloy Rh$_{2}$CuSn (RCS) [2] have been used to build test hard disk drive [3]. In this work, we investigate the mechanism of spin dependent interface scattering for (001) CMG/Ag/CMG (Case1) and (110) CMG/RCS/CMG (Case2) models on the basis of ab-initio electronic structure calculations. We find that in both cases GMR has significant contribution from the spin dependent interface scattering. We propose new binary intermetallic spacer materials Al$_{2}$Au and Cu$_{3}$Sn as an alternative to Ag and RCS spacers. \\[4pt] [1] T.Iwase et.al. Appl.Phys.Express, \textbf{2}, 063003 (2009).\\[0pt] [2] K. Nikolaev et.al. App.Phys. Lett., \textbf{94}, 222501 (2009)