Partial Structural transformation of NiMn in Exchange biased Fe20Ni80/Ni30Mn70/Fe20Ni80 thin films

Abstract

Features of crystal structure and exchange bias of annealed Fe20Ni80/Ni30Mn70/Fe20Ni80 thin films are investigated. Temperature dependences of hysteresis loops reveal that for a sample with a thicker FeNi bottom layer a blocking temperature exceeds a Néel temperature of A1 -NiMn by 20K, while for a sample with a thinner FeNi bottom layer a blocking tem-perature is larger than the Néel temperature by 140K. An explanation of the influence of the bottom FeNi layer on the phase transformation in NiMn is proposed.