An X-ray study of non-zero nickel moment in a ferromagnetic shape-memory alloy

The existence of a magnetic moment at the nickel sites in ferromagnetic shape-memory alloys (FSMA) has long been speculated. Using a state-of-the-art X-ray magnetic circular dichroism (XMCD) technique we found that Ni 3d moments indeed exist in Ni–Mn–Ga-based FSMA. Band-structure calculations were used to simulate the XMCD spectra and estimate this moment to be ∼0.33μB. Such a Ni moment plays a critical role in the dispersions of non-collinear spin structures, which determine the finite-temperature magnetic properties.