Thermal expansion of Ni$_{2.08}$Mn$_{0.96}$Ga$_{0.96}$ alloy

The temperature dependence of the thermal expansion of polycrystalline Ni$_{2.08}$Mn$_{0.96}$Ga$_{0.96}$ alloy samples is studied in the as-cast state and after homogenizing annealing. A sample in which twins are mainly oriented normal to the sample length shortens jumpwise during the martensitic transformation. A sample in which twins are parallel to its length elongates jumpwise. After annealing, both samples do not exhibit a jumplike change in length during the phase transformation. When an annealed sample is cooled in a magnetic field, its length again changes jumpwise in the phase transformation range.