Effect of Pr doping on the properties of Bi0.5−xPrxCa0.5MnO3 (0≤x≤0.50) manganites

In this work, we report the temperature dependent electron spin resonance (ESR) and magnetization (M) studies of Bi0.5−xPrxCa0.5MnO3 (0≤x≤0.50) manganites synthesized by the sol–gel method. The x-ray diffraction (XRD) data analysis indicates that 6s2 lone pair character of Bi3+ ions is dominant in undoped sample and it changes to constrained type when doped with Pr at Bi site. The charge ordering temperature (TCO) decreases from 327 K to 250 K as x increases from 0 to 0.15. The TCO value remains at ~250 K with further increase in Pr content. The nonlinear behavior of ESR signal linewidth (ΔH) as a function of temperature above TCO, observed for doped samples is an indication of strengthening of electron spin–lattice interactions. The sharp rise in M value below 45 K for undoped sample and below 115 K for doped samples is characteristic of ferromagnetic (FM)-cluster glass behavior. The results are discussed in view of the effects of Pr doping on 6s2 lone pair character of Bi3+ ions, disorder in the system and changes in the surface/volume ratio of the grains.