Effect of Ca doping on the magnetic properties of Nd0.5Sr0.5MnO3 studied by electron spin resonance

Abstract The magnetic properties of Ca-doped Nd 0.5 Sr 0.5 MnO 3 have been studied by electron spin resonance (ESR) and dc magnetization measurements. The antiferromagnetic order and charge order are found to occur separately at T N =200 K and T co =150 K, respectively. Compared to the undoped Nd 0.5 Sr 0.5 MnO 3 , the ferromagnetic correlations are suppressed by doping of the small Ca 2+ ion. In addition, the antiferromagnetic transition temperature is enhanced to 200 K, which can be explained by an increase of superexchange interaction between Mn 3+ and Mn 4+ ions as their distance decreases.