A-site deficiency effects on the structural and magnetic properties of La0.7Sr0.3-x square xCoO3 cobaltites

作者：Amor A Ben; Koubaa M; Cheikhrouhou Koubaa W; Cheikhrouhou A^*

来源：Journal of Alloys and Compounds, 2009, 467(1-2): 78-82.

DOI：10.1016/j.jallcom.2007.12.030

• Cobaltites
• Magnetic properties
• Spin state
• Deficiency

Structural and magnetic properties of La0.7Sr0.3-x square xCoO3 (0 <= x <= 0.15) samples have been investigated. Powder samples have been synthesized using the solid state reaction method at high temperature. All our samples crystallize in the rhombohedral structure with R3c space group. With increasing Sr-deficiency amount, the unit cell volume decreases from 341.4 angstrom(3) (x = 0) to 338.2 angstrom(3) (x = 0.15). Our samples exhibit thermo-magnetic irreversibility behavior in the magnetization data in a magnetic applied field of 50 mT, which indicates the absence of long range ferromagnetic order. The Curie temperature decreases from 225 K (x = 0) to 180 K (x = 0.1). Sample with high deficient amount (x = 0.15) becomes predominantly spin glass phase. The effective magnetic moments values obtained from the Curie constant are close to that of the Co3, (intermediate spin configuration) and Co3 (low spin configuration) for 0 <= x <= 0.125 and Co3 (low spin configuration) and Co4 (low spin configuration) for x = 0.15.

• 出版日期2009-1-7