Influence of A-site cation disorder on structural and magnetocaloric properties of Nd sub(0.7-x)La sub(x)Sr sub(0.3)MnO sub(3) (x=0.0, 0.1, 0.2 & 0.3)

• Published in: Journal of rare earths 2015-10, Vol.33 (10), p.1072-1080
• Main Authors: Vadnala, Sudharshan, Pal, Prem, Asthana, Saket
• Format: Article
• Language: English
• Subjects: Disorders; Entropy; Magnetic properties; Magnetization; Physical properties; Rare earth metals; Refrigeration; Transition temperature
• ISSN: 1002-0721
• DOI: 10.1016/S1002-0721(14)60528-7

In the present research, the influence of A-site ionic size disorder on structural, magnetic and magnetocaloric properties of Nd sub(0.7-x)La sub(x)Sr sub(0.3)MnO sub(3) (for x=0.0, 0.1, 0.2 & 0.3) compounds were investigated. These compounds were synthesized by solid state reaction route and crystallized in orthorhombic structure with Pnma space group. An average ionic radius increased with La-substitution which influenced the physical properties such as the magnetic entropy varying from 4.78 J/kg times K (for x=0.0) to 3.55 J/kg times K (for x=0.3) and the maximum magnetization at 5 K changing from 3.92 mu sub(B) (for x=0.0) to 3.59 mu sub(B) (for x=0.3). The change in maximum magnetic entropy decreased with increase of A-site average ionic radius. The decrease in magnetic entropy indicated the suppression of lattice disorder that influenced the spin-lattice coupling. The ferromagnetic transition temperature shifted toward room temperature with La substitution. As increased, the phase transition changed from first order (for x=0.0) to second order (for x> or = 0.1) and the refrigeration capacity increased to a significant level. The modest change in magnetic entropy over a wide range of transition temperature might be useful for future active magnetic refrigeration technology.