Non-volatile high-temperature shell-magnetic pinning of Ni-Mn-Sn Heusler precipitates obtained by decomposition under magnetic field

The thermodynamic instability of the off-stoichiometric Ni49.8Mn45.1Sn5.1 martensitic Heusler causes it to decompose into ferromagnetic Ni50Mn25Sn25 precipitates and an antiferromagnetic NiMn matrix. If the decomposition takes place under an applied magnetic field, the shell of the precipitates acquires a preferred spin orientation that is strongly pinned by the anisotropy of the matrix. The pinning leads to a large vertical shift in the field dependence of the magnetization even at temperatures as high as 500 K. The positive remanence remains permanent even when the magnetic field is cycled or when the sample is directionally manipulated with respect to the external field, providing a non-volatile magnetic-field-proof memory as a further functionality to those existing in martensitic Heuslers.