Magnetic Properties of Fe/Cu Codoped ZnO Nanocrystals

Viswanatha, Ranjani and Naveh, Doron and Chelikowsky, James R and Kronik, Leeor and Sarma, DD (2012) Magnetic Properties of Fe/Cu Codoped ZnO Nanocrystals. In: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 3 (15). pp. 2009-2014.

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Abstract

Free-standing ZnO nanocrystals simultaneously doped with Fe and Cu with varying Fe/Cu compositions have been synthesized using colloidal methods with a mean size of similar to 7.7 nm. Interestingly, while the Cu-doped ZnO nanocrystal remains diamagnetic and Fe-doped samples show antiferromagnetic interactions between Fe sites without any magnetic ordering down to the lowest temperature investigated, samples doped simultaneously with Fe and Cu show a qualitative departure in exhibiting ferromagnetic interactions, with suggestions of ferromagnetic order at low temperature. XAS measurements establish the presence of Fe2+ and Fe3+ ions, with the concentration of the trivalent species increasing in the presence of Cu doping, providing direct evidence of the Fe2+ + Cu2+ sic Fe3+ + Cu+ redox couple being correlated with the ferromagnetic property. Using DFT, the unexpected ferromagnetic nature of these systems is explained in terms of a double exchange between Fe atoms, mediated by the Cu atom, in agreement with experimental observations.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY LETTERS
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copyright for this article belongs to the American Chemical Society
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	13 Feb 2013 10:37
Last Modified:	13 Feb 2013 10:37
URI:	http://eprints.iisc.ac.in/id/eprint/45351

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