Structural, magnetic, magnetocaloric properties and critical behavior of La0.6Bi0.1Sr0.3−xCaxMn0.9Cu0.1O3 manganites (with x = 0.1 and 0.15)

Abstract

The present paper investigates the influence of Ca- doping on the structural, magnetic, magnetocaloric properties and the critical behavior of La0.6Bi0.1Sr0.3−xCaxMn0.9Cu0.1O3 specimens (with x = 0.1 and 0.15). Powder X-ray diffraction revealed the coexistence of rhombohedral (R-3c) and tetragonal (I4/mcm) phases. The temperature dependence of magnetization suggests that samples underwent a ferromagnetic-paramagnetic transition in the vicinity of the Curie temperature (TC). According to the Banerjee criterion, the magnetic phase transition is of a second-order type. The maximum of the magnetic entropy change (-ΔSMmax) was found to be 3.66 J Kg−1 K−1 and 3.74 J Kg−1 K−1 for × = 0.1 and × = 0.15 respectively, under a field change of 5 T. The modified Arrott plot, the Kouvel-Fisher procedure and the critical isotherm were used to determine the critical parameters values of β, γ and δ. All the obtained values of the critical exponent turned out to be close to the value of the theoretical 3D-Ising model. The reliability of the critical exponent was further checked through different methods, such as the Widom scaling relationship and the magnetic equation.