Dy-Doped La0.51Sr0.49MnO₃ nanoparticles: Tuning structural and magnetocaloric properties via Sol-Gel synthesis for energy-efficient applications

• Powders of La 0.51 Sr 0.49 MnO 3 doped with Dy 3+ were produced using an improved sol-gel process at 1000 °C. • XRD, SEM, XPS, M(T) and MCE were investigated. • Doping with Dy 3+ allows easier for the Griffith's phase to manifest. • La 0.51 Sr 0.49 MnO 3 show a large MCE close to room temperature. • The RCP value of the La 0.51 Sr 0.49 MnO 3 is approximately 95 % of the typical refrigerant gd material under 5Tesla. We report the structural and magnetic properties of sol-gel-synthesized Dy-doped La 0.51 Sr 0.49 MnO 3 nanoparticles, which average ≈ 27–29 nm in size. The chemical composition was confirmed using energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The magnetization behavior of the samples showed clear evidence of a transition from ferromagnetic to paramagnetic states in all three cooling and warming processes: Zero Field-Cooled Warming, Field-Cooled Cooling, and Field-Cooled Warming. The Curie temperature exhibits a drop as the concentration of Dy 3+ increases, from 372 K to 317 K. Approximately 95 % of the average refrigerant Gd material under 5T is found in the relative cooling power values of the La 0.51 Sr 0.49 MnO 3 sample, which range from 62 to 387 J/kg when the applied magnetic field is changed from 1T to 5T. In maintaining with the mean-field theory, the critical exponents were determined to be (β = 0.541 and γ = 0.991 for Dy0.00), (β = 0.559 and γ = 0.954 for Dy0.045), and (β = 0.570 and γ = 1.103 for Dy0.09). Dysprosium doping does not alter the universality class, indicating that the material's fundamental behavior remains unaffected. This nanomaterial has a reasonably strong magnetocaloric response and is inexpensive, making it a possible material for active magnetic refrigerators. RCP values of the Dy 0.00 sample exhibit a range of 62 to 387 J/kg when the applied magnetic field is varied from 1 to 5T, which is approximately 95 % of the typical refrigerant Gd material under 5Tesla.