Transferred Hyperfine Interaction and Spin-Lattice Relaxation Time in a CsCuCl₃ Single Crystal

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Magnetic susceptibility and paramagnetic shift for central transition of ¹³³Cs NMR in the single crystal CsCuCl₃ which has transition temperature T_N=10.5 K have been measured in the temperature range of 4.2-300 K. From experimental result, we have obtained the transferred hyperfine interaction due to the transfer of spin density from the Cu²⁺ ion to the Cs⁺ ion in CsCuCl₃ single crystal. The transferred hyperfine interaction can be expressed by the linear equation H_hf=[3.54 T+2.84] (Oe) in the temperature range of 50-300 K; the H_hf increases with increasing temperature. ¹³³Cs spin-lattice relaxation time of ¹³³Cs NMR in the CsCuCl₃ single crystal was also measured in the same temperature range. The temperature dependence of 1/T₁ is nearly constant in the paramagnetic phase, while relaxation rate near T_N exhibits remarkable change, indicating a drastic alternation of spin dynamics at the Neel temperature.