Soft x-ray magnetic circular dichroism study of Mn-Ir/Co-Fe bilayers with giant exchange anisotropy

Abstract

Soft x-ray magnetic circular dichroism (XMCD) and element-specific magnetic hysteresis (ESMH) measurements were performed in transmission mode on Mn73 Ir27 10 nm Co70 Fe30 2 nm bilayers with different chemical orderings of the Mn-Ir layer.The unidirectional anisotropy constant was 0.55 erg cm2 for the disordered Mn-Ir layer and 1.18 erg cm2 for the ordered Mn-Ir layer. The XMCD signal of Mn was observed, which means the induced ferromagnetic component of Mn spins through the exchange coupling at the interface. No vertical offset of the Mn ESMH loops was observed for either the disordered or the ordered bilayers, which means that insignificant uncompensated Mn spin was pinned at the interface to induce exchange bias on the Co-Fe layer. © 2006 American Institute of Physics.