An Electron Paramagnetic Resonance Study of Phase Segregation in Nd0.5Sr0.5MnO3

We present results of an electron paramagnetic resonance (EPR) study of Nd1−xSrxMnO3 with x = 0.5 across the paramagnetic to ferromagnetic, insulator to metal transition at 260 K (Tc) and the antiferromagnetic, charge ordering transition (TN = Tco) at 150 K. The results are compared with those on Nd0.45Sr0.55MnO3 which undergoes a transition to a homogeneous A-type antiferromagnetic phase at TN = 230 K and on La0.77Ca0.23MnO3 which undergoes a transition to coexisting ferromagnetic metallic and ferromagnetic insulating phases. For x = 0.5, the EPR signals below Tc consist of two Lorentzian components attributable to the coexistence of two phases. From the analysis of the temperature dependence of the resonant fields and intensities, we conclude that in the mixed phase ferromagnetic and A-type antiferromagnetic (AFM) phases coexist. The x = 0.55 compound shows a single Lorentzian throughout the temperature range. The signal persists for a few degrees below TN . The behaviour of the A-type AFM phase is contrasted with that of the two ferromagnetic phases present in La0.77Ca0.23MnO3 . Corresponding author, Email address: [email protected]