Influence of Ga substitution on the magnetic ordering of Nd ions in NdBa<inf>2</inf>Cu<inf>3 - x</inf>Ga<inf>x</inf>O<inf>7 - y</inf> at low temperatures

The temperature dependence of magnetic specific heat and magnetic susceptibility of Ga substituted Nd-123 compounds has been investigated at low temperatures. The magnetic ordering of the Nd3+ ions changes remarkably with the Ga concentration. The nature of the magnetic ordering is analysed using different magnetic models. The results are compared with those reported for pure unsubstituted NdBa2Cu3O7 - y samples with various oxygen contents. The magnetic susceptibility data are analysed in the light of crystalline electric field effect (CEF) of different symmetry. The importance of CEF effects in determining the nature of magnetic ordering is explained. © 1995.