Influence of Al substitution in PrBa2Cu3O7-δ single crystals

The role of Al substitution in single crystals of PrBa2Cu3O7-delta (PBCO) has been investigated using low temperature magnetic susceptibility and heat capacity measurements. The crystal composition and the amount of impurity have been determined using electron probe microanalysis (EPMA) and the lattice parameters have been determined using X-ray diffraction. Heat capacity measurements on single crystals of PrBa2Cu3-yAlyO7-delta reveal a sharp peak at 16.6 K for y = 0.0 originating from an antiferromagnetic ordering of the Prion moments (T-N) and broader transitions at approximate to 10 K for y = 0.25 and approximate to 5.3 K for y = 0.4. Subtle anomalies are also found at these temperatures in the magnetic susceptibilities. The present results along with the neutron diffraction studies demonstrate the deleterious role of Al on the magnetic properties in this sample. (C) 1998 Elsevier Science B.V. All rights reserved.