Magnetic Properties Of Ni50mn34.8in15.2 Probed By Mossbauer Spectroscopy

Structural and magnetic properties of a Ni50Mn34.8In15.2 ferromagnetic shape memory alloy doped by Fe-57 at the Mn sites have been studied by x-ray diffraction, Mossbauer spectroscopy and superconducting quantum interference device magnetometry. Obtained experimental results have disclosed unique magnetostructural transition from a high-temperature ferromagnetic austenitic phase to a low-temperature paramagnetic martensitic phase at M-f = 290 K. Complex magnetic ordering which can be classified as a cluster glass state is formed in Ni50Mn34.3 (Fe0.5In15.2)-Fe-57 on further cooling below T-C(M) = 162 K. The abnormal magnetostructural transition observed in Ni50Mn34.3 (Fe0.5In15.2)-Fe-57 is suggested to originate from the weakening of exchange interactions due to an abrupt change in Mn-Mn interatomic distances occurring upon the martensitic transformation.