Short-range ferromagnetic order in perovskite manganite La0.62Er0.05Ba0.33Mn0.95Fe0.05O3

Abstract

The critical phenomena of a high quality La0.62Er0.05Ba0.33Mn0.95Fe0.05O3 sample are comprehensively studied using dc magnetometry in the vicinity of paramagnetic to ferromagnetic second order phase transition. The critical exponents are estimated through various techniques such as Modified Arrott plot, Kouvel–Fisher plot and critical isotherm technique. In comparison with the values given by standard models, the critical exponents β, γ and δ in our case are close to those expected from the three-dimensional Ising model (β = 0.322 ± 0.004, γ = 1.175 ± 0.002 and δ = 4.415 ± 0.02 at an average TC = 256.53±0.06 K). This proves the existence of a short-range ferromagnetic order in La0.62Er0.05Ba0.33Mn0.95Fe0.05O3. Thus, the scaling law γ + β = δβ is fulfilled. With these critical exponents, the isothermal magnetization data around TC fall into two branches of a universal function M(H, ε) = |ε|β f±(H/|ε|β+γ) where ε = (T−TC)/TC is the reduced temperature.