Anisotropic Cu Knight shift and magnetic susceptibility in the normal state of YBa2Cu3O7

Abstract

Precise measurements of the Knight shift at Cu(1) (chain) and Cu(2) (plane) sites have been made in the normal state of a Y${\mathrm{Ba}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ powder sample, for which the $c$ axis of each grain has been aligned in a magnetic field. By combining these data with the Knight shift data in the superconducting state and the anisotropic magnetic susceptibility, it is shown that (1) the anisotropy of the magnetic susceptibility is mainly due to the orbital moment of the $3d$ electrons, (2) the magnitude of the spin contribution to the Knight shift is similar at both sites, and (3) the isotropic part of the Cu hyperfine field is large and positive (112 kOe/${\mathrm{\mu }}_{\mathit{B}}$).