New phase transition studied by proton magnetic resonance in a N(CH3)(4)(2)CuCl4 single crystal

摘要

The proton NMR line width and spin-lattice relaxation rate in a N(CH3)(4)(2)CuCl4 Single crystal have been investigated in the temperature range of 140-340 K. A large discontinuity in the curve of the spin-lattice relaxation rate shows near 200 K: this curve corresponds to a new phase transition. The activation energies were determined at each phase from the spin-lattice relaxation times. The large change in the activation energy at 200 K indicates that the N(CH3)(4) groups are significantly affected during this transition. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. References: 12