Electron spin resonance probed competing states in NiMnInSi Heusler alloy

Shape memory Heusler alloy Ni50Mn35In12Si3 is investigated with electron spin resonance (ESR) technique in a temperature range of 200-300 K. ESR is a dynamic probe allowing us to separate the responses from various magnetic phases, thus to study the complex phase transitions. The sample shows three transition temperatures: TcA (271 K), TM (247 K) and TcM (212 K), where TcA is the Curie temperature of austenitic phase, TM and TcM are the temperatures of magnetostructural martensitic transition and the Curie temperature of martensitic phase, respectively. Furthermore, ESR data reveals the coexistence of two magnetic modes in whole temperature range of 200-300 K. Particularly in martensitic phase, two magnetic modes are attributed to two different kinds of lattice deformation, the slip and twinning deformations.