Abstract
The Rb87 spin-lattice relaxation time T1 and spin-spin relaxation time T2 of RbCdCl3 and Rb4CdCl6 single crystals grown by the slow evaporation method were measured over the temperature range of 160–410K. In the case of the RbCdCl3 crystal, changes were observed in the Rb87 T1−1 near 340, 363, and 395K, which correspond to phase transitions. The abrupt decrease in T1−1 observed at 395K is due to a shortening in the c direction as a result of a phase transition from a tetragonal to a cubic structure. We suggest that the cubic Rb environment is favored above 395K, which causes relaxation and averages out the quadrupolar splittings. On the other hand, the Rb87 T1 in Rb4CdCl6 decreased with increasing temperature, and no phase transitions were observed in the temperature range considered. For both RbCdCl3 and Rb4CdCl6, the relaxation rate of Rb was found to be proportional to the square of the temperature, indicating that the relaxation proceeds via a Raman process. This behavior for the electric-quadrupolar-type RbCdCl3 and Rb4CdCl6 crystals stands in contrast to a previous report that the relaxations in Cs2CuCl4 and Cs2CoCl4 crystals with the magnetic relaxation type proceed via single-phonon processes. Therefore, the relaxation mechanism in crystals with an electric quadrupolar NMR interaction mechanism is completely different from that in crystals with magnetic-type NMR behavior.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
