Structural, magnetic, magnetocaloric and critical behavior studies in the vicinity of the paramagnetic to ferromagnetic phase transition temperature in [formula omitted] compound

Abstract

This article comprises of the structural, magnetic, magneto-caloric and critical behavior study of single phase perovskite manganite LaMnO3+δ sample synthesized by traditional Solid State route. X-ray powder diffraction (XRD) at room temperature indicates the single phase trigonal crystalline structure of LaMnO3+δ with hexagonal setting R3‾c. Magnetic, magnetocaloric and critical behavior are studied using temperature dependent magnetization (M−T) and applied magnetic field dependent magnetization (M−H) data probed by Physical Property Measurement System (PPMS). The second order ferromagnetic to paramagnetic (FM-PM) phase transition is observe at Curie temperature (TC ∼ 180 K). This phase transition is responsible for maximum entropy change (ΔSMmax) of 0.451(1) J/kg K at applied magnetic field of 6 Tesla with relative cooling power (RCP) of 54.293(5) J/kg. At TC, the order of magnetic phase transition is examined by employing Modified Arrott plots (MAP), Kouvel Fisher (KF) and simple isotherm analysis technique. The obtained values of critical exponent’s β ≈ 0.365 ± 0.06, γ ≈ 1.14 ± 0.04 and δ ≈ 4.16 ± 0.10 elaborate that the magnetic phase transition coordinated well with the 3D-Heisenberg model at TC ≈ 180 K and are confirmed by scaling equations of state. Similarly the change in magnetic entropy (ΔSM) versus applied magnetic field recorded complies with the power law ΔS = (H)n with n = 0.64 at TC = 180 K.