Abstract
X-ray powder diffraction, magnetization measurements, and differential thermal analysis (DTA) of polycrystalline MnBi were carried out in zero magnetic field as will as in magnetic fields of up to 14 T and in the temperatures range of 300-773 K, in order to investigate magnetic phase transition. In zero magnetic field, a magnetic phase transition from ferromagnetic to paramagnetic state is exhibited at temperature (Tt) of 628 K, accompanied by decomposition. With increasing magnetic field up to 14 T, Tt increases linearly with the rate of 2 KT-1. A metamagnetic transition between the paramagnetic and field-induced ferromagnetic states was observed just above Tt. The exothermic and endothermic peaks were detected in the magnetic field dependence of DTA signals in the interval of 626-623 K, which relates to the metamagnetic transition. The obtained results are discussed on the basis of a mean field theory.
