Observation of spontaneous magnetization jump and field-induced irreversibility in Nd5Ge3

We report the observation of spontaneous and ultra-sharp jumps in the low-temperature magnetization isotherms of polycrystalline Nd5Ge3. Field-induced and ultra-sharp jumps are also seen in resistivity and heat capacity data. These jumps are accompanied by field-induced irreversibility. The consistency seen in these three data clearly shows that the spin, electronic and lattice states are strongly coupled. Time-induced growth of the ferromagnetic phase is observed at a constant field and temperature, implying the metastability of the magnetic phase in the low field region. Various experimental findings point towards a strong field-induced magneto-structural irreversibility in this compound.