ESR Studies on ${\rm Bi}_{0.5}{\rm Ca}_{0.5}{\rm Mn}_{0.95}{\rm TE}_{0.05}{\rm O}_{3}$ (${\rm TE}={\rm V}$, Cu and Zn)

In this work, the effect of transition element ( TE=V, Cu, and Zn) substitution at Mn site on the electron spin resonance (ESR) of Bi
_0.5
Ca
_0.5
MnO
₃
was explored. The temperature (T) dependent double integrated intensity (DI) and peak to peak linewidth provide the estimation of charge ordering (CO) temperature T
_CO
, long-range antiferromagnetic (AFM) onset temperature, T
_O
, ordering temperature, T
_N
, and the information about the magnetic interactions. The T
_CO
values are 317 K, 317 K, 321 K, and 311 K for undoped, V, Cu, and Zn doped samples, respectively. It is noticed that V doping sharpens the CO transition, whereas Cu and Zn doping smears the CO transition. The temperature dependent magnetization measurements support the ESR observations. In the temperature range T >; T
_CO
, ferromagnetic (FM) correlations dominate. In the temperature range T
_CO
>; T >; T
_O
, the samples are in the paramagnetic (PM+CO) phase. The AFM interactions dominate in the doped samples in this temperature range. The orbital ordering (OO) sets in progressively with decreasing temperature leading to onset of long-range AFM ordering at ~ 200 K for undoped and in the range 190-170 K for doped samples. The present study shows the strong competition between FM and AFM correlations as a function of temperature and composition of the sample.