Impact of Polymeric precursor and Auto-combustion on the Structural, Microstructural, Magnetic, and Magnetocaloric Properties of La0.8Sr0.2MnO3

TL;DR

This study compares two synthesis methods for La0.8Sr0.2MnO3 nanopowders, revealing differences in structural, magnetic, and magnetocaloric properties, and identifies their potential for eco-friendly cooling applications.

Contribution

It provides a comparative analysis of Pechini and auto-combustion synthesis methods on La0.8Sr0.2MnO3's properties, highlighting their suitability for magnetocaloric applications.

Findings

LSMO-PC has larger nanoparticles (~495 nm) than LSMO-AC (~195 nm).

Larger magnetic entropy change in LSMO-PC at 340 K (-1.69 J/kg.K).

Both samples show promise for room-temperature magnetocaloric applications.

Abstract

In this work, La0.8Sr0.2MnO3 (LSMO) nanopowders are synthesized using two different methods: Pechini (LSMO-PC) and auto-combustion (LSMO-AC). Nanoparticle sizes, structural, magnetic, and magnetocaloric properties were determined and compared. The X-ray diffraction confirms the coexistence of two phases; rhombohedral symmetry with space group R-3c and orthorhombic symmetry with space group Pbnm, with the rhombohedral phase dominating. The scanning electron microscope images show that LSMO-PC has larger nanoparticle sizes (~495 nm) than LSMO-AC (~195 nm). The samples exhibit ferromagnetic properties with distinct hysteresis loops and Curie temperatures 340 K and 290 K for LSMO-PC and LSMO-AC respectively. The variation of the magnetic entropy was measured indirectly using the Maxwell approach with increasing magnetic field. For LSMO-PC it reaches a maximum -dSM=1.69 J/kg.K at 340 K and dH= 5 T. The associated adiabatic temperature change dTM is 1.04 K. While LSMO-PC demonstrates superior magnetic and magnetocaloric properties, LSMO-AC displays significant magnetocaloric thermal stability. The obtained values make LSMO-PC and LSMO-AC promising candidates for eco-friendly room-temperature magnetocaloric applications.