Transport properties of shell-ferromagnetic Heusler precipitates in decomposed Ni_(49.8)Mn_(45.1)Sn_(5.1) and decomposition limit for Ni_(50)Mn_(50)-_xSn_x alloys

摘要

Shell-ferromagnetism is observed in Mn-rich NiMn-based Heusler alloys as a result of phase-separation. Off-stoichiometric NiMn-based Heusler alloys decompose into a dual-phase composite when annealed under a magnetic field. As a result of this process, an initially anti-ferromagnetic Heusler alloy gains hard-ferromagnetic properties with a nearly 10 Tesla coercive field of a core/shell structured precipitate. In the present study, Ni_(50.1)Mn_(42.1)Sn_(7.8) and Ni_(50.4)Mn_(36.6)Sn_(13.0) alloys are investigated for magnetic and structural instabilities and shell-ferromagnetic decomposition to obtain information on the compositional limits of the decomposition. Furthermore, we investigate the magneto-transport properties of shell-ferromagnets obtained by annealing Ni_(49.8)Mn_(45.1)Sn_(5.1) in a magnetic-field.