NATURE OF PARAMAGNETIC CENTERS ON THE CRYSTAL-SURFACE OF VAN VLECK PARAMAGNETS

Defect paramagnetic centers Tm3+(g = 11.6 +/- 1, initial splitting Del ta less than or equal to 0.3 cm(-1)) have been detected on the crystal surface of a finely dispersed powder of a van Vleck dielectric parama gnet LiTmF4 by the methods of magnetic susceptibility and electron spi n resonance measurements. It is suggested that these centers be used f or dynamic polarization of the nuclei in liquid helium-3 by the solid- effect method. (C) 1995 American Institute of Physics.