Hyperfine interactions and electronic relaxation in YbCl3· 6H2O

Hyperfine interactions and electronic-spin-relaxation effects have been investigated in Yb${\mathrm{Cl}}_3$ · 6${\mathrm{H}}_2$O by the 66.7-keV Mössbauer resonance in ${}_{}{}^{171}{}_{}{}^{}\mathrm{Yb}$. At low temperatures a magnetic hyperfine field of 2900 ± 30 kOe is observed, with negligible quadrupole interaction. Detailed analysis of the hyperfine constants in light of present knowledge concerning $4f$ radial parameters for ${\mathrm{Yb}}^{3+}$ ion and crystal-field constants in this compound give an upper limit for the magnetic Sternheimer shielding coefficient $R_M=0.03\mathrm{}$ and a relation between the electronic shielding parameters $\frac{(1-{\gamma }_{\infty })}{(1-R_Q)(1-{\sigma }_2)}=209\mathrm{}$. The temperature dependence of the spin-relaxation time is compatible with previous measurements of spin-lattice relaxation in this compound, and gives a spin-spin relaxation time of 6 × ${10}^{-9\mathrm{}}$ sec.