Antiferromagnetic resonance in charge ordering state of Pr0.5Ca0.5MnO3-delta single crystal

An antiferromagnetic resonance (AFMR) is observed in the charge ordered ant iferromagnetic phase of Pr0.5Ca0.5MnO3-delta single crystal for the first t ime. Above the Neel temperature, T-N = 173 K, a paramagnetic resonance with g = 2.0 is observed. There is no significant change of the resonance spect ra at the charge ordering transition temperature, T-CO = 242 K. Below TN, a branch of AFMR is found. Since the resonance field of this mode increases linearly as the frequency is decreased, this branch is assigned as the spin -flop mode. Below 60 K. the critical fields, B-C, evaluated as the extrapol ation of this mode to zero frequency agree well with the insulator-metal tr ansition fields, B-CO, at which the melting of the charge-ordering phase oc curs. Present results indicate that the temperature dependence of B-CO is a ffected by the temperature dependence of B-C. (C) 2001 Elsevier Science B.V . All rights reserved.