Spacer layer thickness dependence of exchange coupling in Co-enriched Co-Mn-Si/Cr/Co-Mn-Si epitaxial trilayers

作者：Bosu S^*; Sakuraba Y; Saito K; Wang H; Takanashi K

来源：Journal of Applied Physics, 2011, 110(11): 113901.

DOI：10.1063/1.3663362

Interlayer exchange coupling was investigated in highly Co-enriched (75.6 at. %), i.e., in Co antisite defective Heusler alloy Co-Mn-Si-based epitaxial trilayer structures for a wide range of spacer Cr thicknesses (t(Cr)). The exchange coupling parameters J(1) (bilinear coupling) and J(2) (90 degrees coupling) were estimated from the comparison of experimental and numerical simulations of M-H loops. The comparable contributions of both the bilinear and 90 degrees couplings were observed in a spacer thickness range, t(Cr) similar to 0.3 to 4.2 nm. The relative angle of magnetization at remanence between the bottom and top Co-Mn-Si layers was found to vary from 67 degrees to a maximum of 152 degrees as a result of competition between bilinear and 90 degrees couplings. In contrast to the observation of strong 90 degrees coupling without any detectable bilinear type 180 degrees coupling in almost stoichiometric and chemically B2-ordered Co(2)MnSi-based trilayer structures in a previous study, the results in this study clearly indicated the importance of the effect of chemical ordering on dominating 90 degrees coupling in Heusler alloy-based structures.

• 出版日期2011-12-1