Charge-ordered antiferromagnetic to ferromagnetic phase transition in cr-doped Nd _0.5Ca _0.5Mn _1-x Cr _x O ₃: EMR and Magnetization Study

The Cr-doped rare-earth manganites Nd _0.5Ca _0.5Mn _1-x Cr _x O ₃ (x = 0.03, 0.05, 0.10) are studied by electron magnetic resonance (EMR) and magnetization measurements in the paramagnetic as well as in the ferromagnetic phase. The magnetization measurements show that the charge-ordered antiferromagnetic phase decreases at the expense of ferromagnetic metallic phase and for Cr doping of x = 0.1, the charge-ordered phase melts completely. The EMR shows multiple signals for all three compositions in the ferromagnetic phase indicative of an anisotropic ferromagnetic phase. The difference between the shift of the high-field and low-field signals decreases with Cr doping, indicating that the magnetic anisotropy decreases with the Cr doping. In the paramagnetic phase the EMR line width follows Causa's model as observed in other colossal magnetoresistant manganites.