Singh, Shiva Kumar and Kumar, Praveen and Husain, M. and Kishan, Hari and Awana, V. P. S. (2010) Structural and magnetic properties of Co1−xFexSr2YCu2O7+δ compounds. Journal of Applied Physics, 107 (6). 063905-1. ISSN 1089-7550

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Abstract

Here we study the structural and magnetic properties of the Co1−xFexSr2YCu2O7+δ compound (0 ≤ x ≤ 1). X-ray diffraction patterns and simulated data obtained from Rietveld refinement of the same indicate that the iron ion replacement in Co1−xFexSr2YCu2O7+δ induces a change in crystal structure. The orthorhombic Ima2 space group structure of Co-1212 changes to tetragonal P4/mmm with increasing Fe (x ≥ 0.5) ion. The XPS studies reveal that both Co and Fe ions are in mixed states of 3+/4+ for the former and 2+/3+ in case of later. The magnetization with temperature follows Curie–Weiss behavior, in the range of 150–300 K and short magnetic correlations/spin glasslike features below 150 K. The observed magnetic behavior is due to competition of antiferro/ferromagnetic exchange interaction of Co3+ [intermediate spin (IS)]-O–Co3+ (IS)/Co4+ [low spin (LS)] and Fe3+ [high spin (HS)]-O–Fe2+ (LS)/Fe3+ (HS)/Co3+ (IS)/Co4+ (LS) states. Although none of the studied as synthesized samples in Co1−xFexSr2YCu2O7+δ are superconducting, the interesting structural changes in terms of their crystallization space groups and the weak magnetism highlights the rich solid state chemistry of this class of materials.

Item Type:	Article
Subjects:	Physics
Divisions:	UNSPECIFIED
Depositing User:	Ms Neetu Chandra
Date Deposited:	11 Jul 2012 08:08
Last Modified:	11 Jul 2012 08:09
URI:	http://npl.csircentral.net/id/eprint/325

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