Ritu Vishnoi

Structural and magnetic properties of magnetron sputtered Ni–Mn–Sn ferromagnetic shape memory alloy thin films

In the present study, structural and magnetic properties of Mn-rich, off-stoichiometric, nanocrystalline Ni–Mn–Sn ferromagnetic shape memory alloy thin films, grown on Si (100) substrates at 550u2009°C by dc magnetron sputtering have been systematically investigated. The crystallization, surface morphology, and structural features were studied using x-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy. The structural transition from austenite to martensite was observed with an increase of Mn content. Austenitic phase with mixed L21/A2+B2 structure has been observed at room temperature in Ni52.6Mn23.7Sn23.6 (S1) and Ni51.5Mn26.1Sn22.2 (S2) films, while those with composition of Ni58.9Mn28.0Sn13.0 (S3) and Ni58.3Mn29.0Sn12.6 (S4) show martensitic phase with 14M modulated monoclinic structures. Field induced martensite-austenite transformation has been observed in magnetization studies using superconducting quantum interference device magnetometer. Temperature dependent mag...