Role of Y and Ba doping on phase separation and magnetization steps in Nd0.5Sr0.5MnO3 by electron spin resonance

Electron spin resonance (ESR) of polycrystalline CMR manganites for Y and Ba doping is studied in the vicinity of the composition Nd0.5Sr0.5MnO3 that shows ferromagnetism below TC=260K, and both antiferromagnetism and charge ordering below TCO=TN=150K. The temperature dependence of magnetic phase transitions was investigated for compositions Nd0.5−xYxSr0.5MnO3 and Nd0.5Sr0.5−xBaxMnO3 with x=0.05 and 0.1, focusing on the effect of the average A-site size 〈rA〉 and the mismatch σ2. Phase separation is reported in compounds with 10% Ba or Y compounds, consistent with their large σ2. Steps in the ESR signals are observed below the transition temperature under low magnetic field.