Nature of paramagnetic centers on the crystal surface of van Vleck paramagnets
Klochkov A. V. , Naletov V. V. , Tagirov M. S. , Tayurskii D. A. , Teplov M. A. , Efimov V. N. , Mamin G. V.
Defect paramagnetic centers Tm3 + (g = 11.6 ± 1, initial splitting Δ =£0.3 cm-1) have been detected on the crystal surface of a finely dispersed powder of a van Vleck dielectric paramagnet LiTmF4 by the methods of magnetic susceptibility and electron spin resonance measurements. It is suggested that these centers be used for dynamic polarization of the nuclei in liquid helium-3 by the solid-effect method.