Revisiting of Specific Heat of Nonsuperconducting PrBCO Ceramics in Orthorhombic Phase: Signature of Magnetic Phase Transitions at Low Temperatures

摘要: The magnetic and electronic contributions of the Pr ions only to specific heat C p (T) entropy S(T) defined by ΔC ΔS(T), respectively, are revisited at low temperatures for nonsuperconducting PrBa 2 Cu 3 O 6+x ceramics with x = 1 0.95. Two small anomalies observed below well-known anomaly due antiferromagnetic (AFM) ordering sublattice Neel temperature T N 17.5 14 K, respectively. first one, which occurs near transition ~ 10.5 ~9.5 is effect previous spin reorientation phase moments. Whereas second appears both states same critical cr 4-5 caused noncollinear reordering subsystem. A phenomenological analysis used in fitting procedure . values associated linear coefficient Δγ found fairly lower than those deduced from measurements on single crystals orthorhombic phase. In addition common contribution (T), characterizes AFM ordering, 5 rather significant Pr-Cu(2) coupling introduces some nonlinear effects. All results discussed compared earlier reports.