Proton spin-lattice relaxation in TMMC [(ch/Sub 3/)/Sub 4/Nmncl/Sub 3/]

Abstract

We examine the temperature and frequency dependence of the proton spin-1attice re1axation rate 1/T 1, as a probe of the electron-spin dynamics of the quasi-one-dimensional exchange-coupled paramagnet TMMC [(CH3) 4NMnC1J. The rate is measured from 5.5-16 MHz and from 1.4 °K to room temperature. An extension of Moriya's magnetic-relaxation theory to the linear-chain system, using the exact classical results for static spin-correlation functions, gives over-all good quantitative agreement between theory and experiment. A sharp minimum in 1/ T 1 at T~/ 18 °K, an w -1/2 dependence on frequency at room temperature and w -1/2 at 1ow temperature, with the externai fie1d paral1e1 to the chain, and the frequency independence of 1/T 1 at room temperature with the fie1d perpendicular to the chain are ali explained by the theory.