Praseodymium and oxygen role on magnetic properties of PrBa ₂ Cu ₃ O _{6+ x}

Abstract

We report on magnetic investigation on PrBa 2 Cu 3 O 6+x compounds (0.4 < x < 1.0) where the Pr 3+ ions exhibit an antiferromagnetic order (AF) at T N ~ 11 K for x ~ 0.5 and 17 K for x ~ 1. For better understanding of the role of the praseodymium and oxygen content on magnetic and transport properties, we measured temperature and field dependence of susceptibility and magnetization of PrBa 2 Cu 3 O 6+x in two oxygenation states x = 0.4 and 0.9. We show that a careful analysis of these data can bring to evidence the existence of several tiny transitions, especially a sharp one around 13 K which may be related to a change of direction of copper moments.