Magnetic phase transitions in Er7Rh3 studied on single crystals

Magnetic phase transitions in Er7Rh3 with the Th7Fe3 type hexagonal structure have been studied on single crystals by measuring magnetization, magnetic susceptibility and electrical resistivity. Er7Rh3 possesses antiferromagnetic state below TN = 13 K. In the ordered state, the two successive magnetic transitions at Tt1 = 6.2 K and Tt2 = 4.5 K were observed. Several field-induced magnetic transitions were also observed along the a- and c-axes below TN; magnetic field H - temperature T phase diagram along the c-axis was constructed. The field-induced magnetic transitions in Er7Rh3 can be explained by the magnetic structure with two magnetic propagation vectors which were derived by the previous neutron diffraction studies. Electrical resistivity shows humps just below the magnetic transition temperatures, TN and Tt1 due to the super-zone gap formation at the Fermi level; these anomalies can also be described by the magnetic structure changes in Er7Rh3.