Room-temperature structure, magnetic, and magnetocaloric properties of (La0.8-xNdx)Sr0.2MnO3(0 ≤ x ≤ 0.2)

Abstract

In this study, the impacts of Nd doping on the structural, morphological, magnetic, and magnetocaloric properties of (La0.8-xNdx)Sr0.2MnO3 (0 ≤ x ≤ 0.2) (LNSMO) have been investigated. LNSMO has been synthesized using the sol-gel technique (SG). XRD analysis revealed that LNSMO has a rhombohedral structure and belongs to the R-3c space group (No. 167). In addition, the XRD refinement using Fullprof software demonstrated that the cell volume and lattice parameters gradually reduced as Nd doping increased, confirming the gradual replacement of the La sites by Nd. The fitting of the Mn 2p peak by X-ray photoelectron spectroscopy (XPS) confirmed that Mn is in mixed valence (Mn3+, Mn4+), which contributes to the double exchange interactions (DE). It is confirmed by M−H that the paramagnetic (PM) - ferromagnetic (FM) transition of LNSMO is a second-order magnetic phase transition. There is a significant change in the magnetocaloric effect (MCE) around room temperature. The results of the magnetization measurements indicate that a reduction in the Curie temperature (Tc) and an increase in the Nd doping cause an increase followed by a decrease in the maximum magnetic entropy change (-ΔSMmax). On the contrary, the relative cooling power (RCP) first decreases and then increases. Therefore, we propose La0.62Nd0.18Sr0.2MnO3 sample with Tc = 300 K, -ΔSMmax = 4.22 J/(kg·K) and RCP = 253.39 (J/kg) under an external magnetic field. This material is potentially one of the candidates that could be used to develop magnetic refrigeration technology.

Keywords

• Perovskite manganites
• Magnetization
• Magnetic entropy change
• RCP