Low temperature magnetization studies of Bi_1-xCa_xMnO₃

The detailed magnetization studies of Bi_1-xCa_xMnO₃ (x= 0.65, 0.70, 0.75, 0.80, 0.85 and 0.90) samples synthesized by sol-gel technique were carried out in the temperature range 5–325K. The magnetization data has been used to get information about magnetic interactions. The results on the present samples are compared with the results on bulk samples to assess the effects of grain size on the estimated values of charge ordering temperature (T_CO), antiferromagnetic (AFM) ordering i.e Neel temperature (T_N). For samples with 0.65 ≤ x ≤ 0.80, the magnetic phase is dominated by FM interactions in the temperature range T > T_CO and coexistence of FM and AFM correlations in the temperature range T_N < T < T_CO. The signature of PM to canted-AFM (C-AFM) transition at ∼ 120K is observed for all compositions. Whereas for samples with x = 0.85 and 0.90, the AFM interactions dominate in the temperature range T > 120 K and canted-AFM ordering is observed below 120 K.