Magnetothermal Properties of NdCo5 –xGax Compounds

The magnetization and magnetocaloric effect (MCE) of NdCo 5 – x Ga x compounds are measured. It is found that the magnetic ordering temperatures of NdCo 5 – x Ga x compounds with Ga substitution fall in proportion to the square of the magnetic moment of the Co sublattice, due to the major contribution from the Co sublattice in the magnetic ordering of these compounds. Reducing the Ga concentration from 1.7 to 1.3 sharply raises the values of both the magnetic ordering temperature and the MCE. With a further decrease in Ga concentration, the magnetic anisotropy of the Co sublattice begins to play an important role, leading to the formation of noncollinear magnetic structures, the emergence of spin-reorientation magnetic phase transitions, and a reduction in the MCE.