Magnetic and magneto-caloric behavior of La0.67-xEuxBa0.33Mn0.85Fe0.15O3 (x = 0.0 and 0.1) nanoparticles

Abstract

The magnetic and magneto-caloric (MC) behavior of La_0.67-xEu_xBa_0.33Mn_0.85Fe_0.15O₃ (x = 0.0 and 0.1) nanoparticles has been investigated in this work. The samples under study were prepared using the sol–gel method. Structural analysis, conducted via X-ray diffraction, revealed that the samples crystallize in an orthorhombic structure with a Pbnm space group. The magnetic data indicate that the compounds exhibit a transition from a ferromagnetic (FM) to a paramagnetic (PM) state as the temperature increases. The Curie temperature values are 170 K and 100 K for x = 0 and 0.1, respectively. At low temperatures and for all samples, the M(µ₀H) curves at various temperatures show the coexistence of antiferromagnetic domains. The Griffiths phase, identified from the temperature dependence of the inverse susceptibility, is observed in these samples. The magneto-caloric (MC) effect was determined from the magnetization versus applied magnetic field up to 7 T at different temperatures (5 K ≤ T \(\le\) 280 K). A broadening of the magnetic entropy change peak and low values of (-ΔS_Max) are highlighted in our samples. For magnetic field µ₀H = 5 T, (-ΔS_Max) reaches maximum values in the order of 0.90 and 0.59 J.K⁻¹.kg¹ for x = 0 and 0.1 respectively. Despite the low values of (-ΔS_Max), important values of the relative cooling power have been observed in our compounds which are 182.81 and 92.72 (JK⁻¹) for x = 0 and 0.1 respectively for µ₀H = 5 T.