Critical slowing down of spin fluctuations in BiFeO3

Scott, J. F. and Singh, M. K. and Katiyar, R. S. (2008) Critical slowing down of spin fluctuations in BiFeO3. Journal of Physics: Condensed Matter, 20 (42). p. 425223. DOI 10.1088/0953-8984/20/42/425223

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Abstract

In earlier work we reported the discovery of phase transitions in BiFeO3 evidenced by divergences in the magnon light-scattering cross-sections at 140 and 201 K (Singh et al 2008 J. Phys.: Condens. Matter 20 252203) and fitted these intensity data to critical exponents a = 0.06 and a' = 0.10 (Scott et al 2008 J. Phys.: Condens. Matter 20 322203), under the assumption that the transitions are strongly magnetoelastic (Redfern et al 2008 at press) and couple to strain divergences through the Pippard relationship (Pippard 1956 Phil. Mag. 1 473). In the present paper we extend those criticality studies to examine the magnon linewidths, which exhibit critical slowing down (and hence linewidth narrowing) of spin fluctuations. The linewidth data near the two transitions are qualitatively different and we cannot reliably extract a critical exponent n, although the mean field value n = 1/2 gives a good fit near the lower transition.

Item Type: Article
Uncontrolled Keywords: 08AREP; IA57;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Journal of Physics: Condensed Matter
Volume: 20
Page Range: p. 425223
Identification Number: 10.1088/0953-8984/20/42/425223
Depositing User: Sarah Humbert
Date Deposited: 30 May 2009 11:55
Last Modified: 23 Jul 2013 09:55
URI: http://eprints.esc.cam.ac.uk/id/eprint/1040

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