Abstract
A rotational-cooling method is employed to obtain proton polarization in crystals of YCl 3·6H 2O doped with Yb 3+ ions. The relaxation behaviour of the protons is investigated as a function of magnetic field H (1 kOe ≲ H ≲ 10 kOe), temperature T (0.05 K ≲ T ≲ 1 K) and concentration c of the rare-earth ions (0.05%≲ c ≲ 1.4%). For concentrations of the Yb ions in the range 0.3 ≲ c ≲ 1.4% the relaxation times are strongly influenced by the dipole-dipole reservoir of the electron spins. The electron-spin-lattice relaxation rate is calculated on the basis of the proton-spin-lattice relaxation rates ( T -1 1n at the lower Yb concentrations. Because the T 1n measurements are reasonally well described by a hexagonal crystal-field interaction on the Yb ions, a hexagonal crystal-field hamiltonian is proposed. Polarization measurements give g min = 0.08 ± 0.01.
Sign-in/Register to access full text options 
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 call
