Irreversible magnetic-field-induced antiferromagnetic to ferromagnetic transition in Nd5Ge3

Magnetic phase transitions in the rare-earth intermetallic compound Nd5Ge3 have been investigated using a single crystal. Magnetic measurements confirm that Nd5Ge3 is in the antiferromagentic state below TN=51 K, in literature. An irreversible magnetic-field-induced antiferromagentic to ferromagnetic transition has been found below Tt=26 K. In this state, a metamagnetic transition takes place in the first magnetizing process; a ferromagnetic state having a remanent magnetization MR is stabilized after removing the external magnetic field. MR does not show noticeable relaxation behavior and a rectangular-type hysteresis loop is maintained in the following magnetization process. As origin of the irreversibility, a martensitic structural phase transition under the external field can be considered. The magnetic-field cooling effect on the magnetic susceptibility indicates the coexistence of a kind of spin-glass state with long-range antiferromagnetic ordering.