Magnetic and structural phase transitions of MnBi under high magnetic fields

High-field x-ray diffraction and magnetization measurements and differential thermal analysis (DTA) were carried out for polycrystalline MnBi with an NiAs-type hexagonal structure to investigate its magnetic and structural phase transitions. The lattice parameter a rapidly decreases below the spin reorientation temperature T SR (=90 K) in a zero magnetic field. The parameter c decreases gradually with decreasing temperature and exhibits an anomaly in the vicinity of T SR . By applying a magnetic field of 5 T, the parameter a increases by ∼0.05% when T