Scaling study of magnetic phase transition and critical behavior in Nd0.55Sr0.45Mn0.98Ga0.02O3 manganite

Highlights: • The sample of Nd_0.55Sr_0.45Mn_0.98Ga_0.02O₃ was synthesized via a solid state reaction route. • The PM to FM phase transition of this sample is found to be of second-order. • The critical behaviors and scaling relation for Nd_0.55Sr_0.45Mn_0.98Ga_0.02O₃ have also been investigated by modified Arrott plot and critical isotherm analysis. • The estimated critical exponents are close to the values for 3D-Ising model. - Abstract: Microscopic magnetic interactions and magnetism can be probed by studying the critical paramagnetic–ferromagnetic phase transition of magnetic materials. In this work, the critical behavior of the lightly Ga-doped manganites Nd_0.55Sr_0.45Mn_0.98Ga_0.02O₃ (NSMGO) has been investigated. Scaling analysis reveals the critical exponents β = 0.308, γ = 1.197, and δ = 4.916, where their self-consistency and reliability are verified by the Widom scaling law and the scaling equation. These exponents indicate that the magnetic phase transition in NSMGO belongs to the anisotropic 3D-Ising universality class. Nevertheless, the asymptotic critical exponents β_eff and γ_eff are found to approach to the values of 3D-Heisenberg model, implying the existence of isotropic short-range magnetic interactions. We suggest that, although the Nd-based manganites possess a strong magnetocrystalline anisotropy, this effect can be partly averaged out in view of the present polycrystalline NSMGO. Therefore, in the asymptotic critical region, the phase transition reveals the crossover from the scaling of 3D-Ising toward 3D-Heisenberg universality class.