Study of the structural phase transitions in RbCuCl3 and CsCuCl3 single crystals with the electric-magnetic-type interactions using a 87Rb and 133Cs nuclear magnetic resonance spectrometer

RbCuCl3 and CsCuCl3 single crystals were grown by the slow evaporation method, and the spin-lattice relaxation times and the resonance lines of the Rb-87 and Cs-133 nuclei in the resulting crystals were investigated using Fourier transform nuclear magnetic resonance (FT NMR) spectrometry. The temperature dependence of the relaxation time of the Rb-87 nucleus in the RbCuCl3 crystals exhibited a discontinuity near T-C2(=260 K), which was attributed to a structural phase transition. Although the Rb-87 relaxation data showed no change indicative of a phase transition at T-C1(=340 K), the splitting of the Rb-87 resonance lines did change abruptly at T-C1, indicating that the Rb-87 nuclei depends on the local environments surrounding these nuclei. For the CsCuCl3 crystals, the relaxation time of the Cs-133 nucleus underwent large, abrupt changes at T-N (=10.5 K) and near T-C (=423 K), which coincide with a magnetic and a structural phase transition, respectively. The RbCuCl3 and CsCuCl3 results are compared with those obtained previously for other ABCl(3) (A=Rb, Cs, B=Cd, Mn) perovskite crystals. (c) 2007 American Institute of Physics.