Martensitic and intermartensitic transitions in Ni50Mn20Cu5Ga21Al4 Heusler alloy

•We studied the martensitic and intermartensitic transitions in Ni50Mn20Cu5Ga21Al4 Heusler alloy.•Intermartensitic transition appears after heat treatment and does not depend on quenching.•While the martensitic transition temperatures and dynamics are quite independent of field and repeated magnetization measurements, the intermartensitic transition, specially the direct one (when cooling) is almost different in each measurement. Intermartensitic and martensitic transitions on polycrystalline Ni50Mn20Cu5Ga21Al4 Heusler alloys were studied through magnetization, heat capacity and electrical resistivity measurements. The occurrence of an intermartensitic transition depends on whether the sample undergoes heat treatment, while the martensitic transition is independent of the annealing process. After an annealing treatment, martensitic and intermartensitic transitions are observed at 264K and 181K respectively, both showing large thermal hysteresis. Both transitions affects the magnetic response of the zero field cooled and field cooled magnetic measurements. Similar effects are also observed on the electrical resistivity and specific heat of the alloys.