Effects of Europium ion doping on the microstructure, magnetic and magnetocaloric effect of La0.8Sr0.2MnO3 manganites

La 0.8- x Eu x Sr 0.2 MnO 3 (LESMO) ( x  = 0.05, 0.10, 0.15) samples were synthesized by the sol-gel (S-G) method. The effect of Eu 3+ doping at the A-site on the microstructure, morphological, and magnetocaloric effect (MCE) of LESMO was investigated. XRD revealed that the LESMO samples had a rhombohedral structure within the R-3c space group. The cell volume ( V ) decreased with increasing Eu 3+ doping. The magnetic properties of LESMO revealed a ferromagnetic-paramagnetic transition around the Curie temperature (T C ) with an increase in the Eu 3+ doping level. Using Banerjee’s criterion and utilizing normalization, it was confirmed that a second order magnetic phase transition (SOMPT) occurs in LESMO near T C . The maximum magnetic entropy change \((-\Delta {S}_{M}^{M{ax}})\) of LESMO ( x  = 0.05, 0.10, and 0.15) was 5.22 J/(kg·K), 4.68 J/(kg·K), and 3.55 J/(kg·K), respectively, under an external magnetic field (H). The relative cooling power ( RCP ) of LESMO was 285.01 J·kg −1 ( x  = 0.05), 289.60 J·kg −1 ( x  = 0.10), and 300.15 J·kg −1 ( x  = 0.15). La 0.65 Eu 0.15 Sr 0.2 MnO 3 exhibits a higher maximum RCP of 300.15 J·kg −1 , equal to 73.2% of that of Gd. Graphical