Study of Landau theory and universal curve on La0.6-xGdxSr0.4MnO3 (x= 0 - 0.1) manganite

Abstract

In this study, the magnetocaloric effect and magnetic properties of La0.6-xGdxSr0.4MnO3 (x= 0-0.1) samples (with the R-3c space group crystalize in rhombohedral structure) synthesized by the Sol-gel method is presented here. The aim of the study is the investigation of the Landau theory and universal curve approach applied to the magnetic entropy change of La0.6-xGdxSr0.4MnO3 (x= 0-0.1) compounds. A universal curve is an important tool that allows us to compare the performance quality of different materials during measurements, regardless of their nature, processing, or experimental settings. Thermodynamic models were used to calculate the MCE. Theoretical and experimental data -∆SM (T) are well-matched in the compounds. The study of the universal curve and Landau theory showed that the nature of the transition is the second-order ferromagnetic (FM) -paramagnetic (PM) magnetic phase transition. From an application point of view, theoretical research confirmed that compounds containing Gd in the La site can be used for magnetic refrigeration technology.

Keywords

• manganite
• landau theory
• universal curve
• magnetocaloric effect
• second-order phase transition