H NMR spin-lattice relaxation studies in Betaine phosphate (BP) - Transition from classical to quantum rotation

Ramanuja, MN and Ramesh, KP and Ramakrishna, J (2006) H NMR spin-lattice relaxation studies in Betaine phosphate (BP) - Transition from classical to quantum rotation. In: Physica Status Solidi B-Basic Solid State Physics, 243 (8). pp. 1929-1938.

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Abstract

We report here the results of our H-1 NMR spin-lattice relaxation time (T-1) studies in betaine phosphate which is ferroelectric below 86 K and antiferroelectric below 81 K. The experiments have been carried out in the temperature range 300 to 4 K, at two Larmor frequencies 11.4 and 23.3 MHz. The T, data (300-100 K) has been analysed using modified BPP equation based on Ikeda's model. CH3 Protons are found to relax other protons via spin diffusion. The low temperature (T < 100 K) T-1 data has been analysed following Lourens model which considers the gradual transition from classical motions to quantum regime. At low temperatures, when classical processes tend to freeze, reorienting groups apparently have minute differences and hence create a distribution in the energy values (E-a and E-01) and pre-exponential factors

Item Type:	Journal Article
Publication:	Physica Status Solidi B-Basic Solid State Physics
Publisher:	Wiley-V C H Verlag Gmbh
Additional Information:	Copyright of this article belongs to Wiley-V C H Verlag Gmbh.
Keywords:	76.60.Es;77.84.Jd.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	25 Mar 2009 07:12
Last Modified:	19 Sep 2010 04:56
URI:	http://eprints.iisc.ac.in/id/eprint/17304

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