Structure, magnetic and magnetiocaloric properties in La1.4Sr1.6-xCaxMn2O7 perovskite compounds

• Published in: Journal of alloys and compounds Vol. 469; no. 1-2; pp. 61 - 65
• Main Authors: ZHAO, X, CHEN, W, ZONG, Y, DIAO, S. L, YAR, X. J, ZHU, M. G
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier 05.02.2009
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric effect, magnetic cooling; Magnetotransport phenomena, materials for magnetotransport; Manganites; Physics; Phase composition; Layered crystals; Doping; Magnetic field effects; Perovskites; XRD; Magnetic transitions; Jahn-Teller effect; Oxide material; Magnetic measurement; Magnetocaloric effects; Solid state reaction; Solid-state reaction; Microstructure; Exchange interactions; Manganites
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2008.02.021

The nominal compositions of La1.4Sr1.6-xCaxMn2O7 (0.0 < = x < = 1.6) have been synthesized using solid-state reaction method. The XRD analyses show that the compounds are pure I4/mmm tetragonal bilayered perovskites phase for x < = 0.8, while they are mixture of a main orthorhombic ABO3-type perovskite and a slight cubic calcium oxide for x > = 1.0. For lightly doped samples (x < = 0.8), the 3D ferromagnetic (FM) transition temperature first declines and then disappears due to the depression of the interlayer exchange interaction by Ca2+ doping. However, the intralayer exchange interaction is strengthened in the x = 0.4 sample on account of large Jahn-Teller distortion of MnO6 octahedra. A large magnetic entropy change of 2.28 J kg-1 K-1 is obtained in the nominal composition La1.4Sr1.6-xCaxMn2O7 (x = 1.6) upon 1 T applied magnetic field, which makes it suitable for sub-room temperature magnetic cooling material.