Magnetic Phase Transition and Exchange Bias in \(\hbox {Ni}_{45}\hbox {Co}_{5}\hbox {Mn}_{35.5}\hbox {In}_{14.5}\) Heusler Alloy

Magnetic properties and exchange bias of \(\hbox { Ni}_{45}\hbox {Co}_{5}\hbox {Mn}_{35.5}\hbox {In}_{14.5}\) ribbons were investigated by vibrating sample magnetometry (VSM) and electron magnetic resonance (EMR). Curie temperatures determined by using VSM and EMR methods are equal to 374 K and 377 K, respectively. Additionally, the EMR measurements revealed the existence of a weak ferromagnetic resonance (FMR) line in the paramagnetic region. The upward deviation of the integral intensity from Curie–Weis low below temperature \(T^*\) and above \(T_\mathrm{C}\) confirms the existence of ferromagnetic phase in this temperature region. Below \(T_\mathrm{C},\) the integral intensity does not saturate, which can suggest the coexistence of different magnetic phases at low temperature range. Additional confirmation on the coexistence of magnetic phases in the sample are asymmetric hysteresis loops associated with the spontaneous exchange bias effect. The dependence of EMR signal on cyclic repetition of measurement is also discussed.