TEMPERATURE DEPENDENCE OF NUCLEAR MAGNETIC RESONANCE AND SPIN-LATTICE RELAXATION TIME OF NA-23 IN A NAMNCL3 SINGLE CRYSTAL

摘要

The temperature dependence of Na-23 (I = 3/2) nuclear magnetic resonance in a NaMnCl3 crystal grown by the Czochralski method has been investigated by employing a Bruker FT NMR spectrometer. From the experimental data, the quadrupole coupling constant and asymmetry parameter are determined in the temperature range of 140 to 380 K. The principal z-axis of the EFG tensor of Na-23, the largest component, is parallel to the crystallographic c-axis. The quadrupole coupling constant of Na-23 is found to be linearly increasing as the temperature increases. We have discussed the transferred hyperfine interaction due to the transfer of spin density from the Mn2+ ion to the Na+ ion in a NaMnCl3 single crystal. In addition, the temperature dependence of the relaxation time T-1(-1) could be fitted by the approximation T-1(-1) = {4.88T - 228.15} (s(-1)). Therefore, we conclude that the dominant contribution to the relaxation rate is explained by the direct process of scattering with a single phonon. [References: 23]