Effect of the partial substitution of K on the structural, magnetic and magnetocaloric properties of brownmillerite oxides La1-xKxSrMn2O5+δ (0.1 ≤ x ≤ 0.3)

The present study investigates the effects of the substitution of potassium K the A-site on the magnetic and magnetocaloric properties of the brownmillerite compounds La1-xKxSrMn2O5+delta (0.1 <= x <= 0.3). Our samples were synthesized using the conventional solid-state reaction at high temperature. The findings from structure studies revealed that all the samples crystallized in the orthorhombic system with a Pnma space group. The properties of magnetic refrigerants may also be affected. Magnetic measurements and Arrott's analysis were used to detect a second-order ferromagnetic phase change in each sample. The Curie temperature T-C decreased with more substitution of potassium content. Arrott plots showed that all samples exhibited a second-order magnetic phase transition. Magnetocaloric effect was calculated in terms of isothermal magnetic entropy change. Additionally, it leads to a decrease in magnetic entropy Delta S-M, as calculated from isothermal magnetization data. For x = 0.1, 0.2, and 0.3, the maximum magnetic entropy change |Delta S-M| around T-C's calculated to be 1.2 J kg(-1) K-1, 1.08 J kg(-1) K-1 and 0.8 J kg(-1) K-1 correspondingly.