Magnetic proximity effect and shell-ferromagnetism in metastable Ni50Mn45Ga5

Abstract

The present study on magnetic and structural properties of Ni(50)Mn(45)G(a)5 confirms that structural metastability is an inherent property of Ni50Mn50-xXx Heusler alloys with X as In, Ga, and Sn. The ternary alloy transforms during temper-annealing into a dual-phase composite alloy. The two phases are identified to be cubic L2(1), Ni50Mn25Ga25, and tetragonal L1(0) Ni50Mn50. Depending on the annealing temperature, the magnetic-proximity effect giving rise to shell-ferromagnetism has been observed when annealing is carried out under an external magnetic field. The upper and lower remanence values M-R(+) and M-R(-) have the same sign even at high temperatures. Such alloys can be promising candidates for heat-and magnetic-field-resistant magnetic recording media. Published by AIP Publishing.