Anisotropy of paramagnetic susceptibility and electronic structure of high-Tc superoconductors

Calculation is fulfilled of the paramagnetic susceptibility x of HTSC with account for the crystal field and spin-orbital interaction. It is obtained that delta x = xparalel - xperpend > 0 when making at the Fermi level of states x2 - y2 and being near them states xy; delta x < 0 for states x2 - y2 and xz, yz. A possibility is discussed for explanation of the susceptibility temperature dependence. It is noted the importance of measurements of spectral and magnetic characteristics in the basal plant, which may be used for determining occupancy of states with different symmetry at the Fermi