Theoretical studies of ⁶³Cu Knight shifts of the normal state of YBa₂Cu₃O₇

Abstract

The 63Cu Knight shifts and g factors for the normal state of YBa2Cu3O7 in tetragonal phase are theoretically studied in a uniform way from the high (fourth-) order perturbation formulas of these parameters for a 3d9 ion under tetragonally elongated octahedra. The calculations are quantitatively correlated with the local structure of the Cu2+(2) site in YBa2Cu3O7. The theoretical results show good agreement with the observed values, and the improvements are achieved by adopting fewer adjustable parameters as compared to the previous works. It is found that the significant anisotropy of the Knight shifts is mainly attributed to the anisotropy of the g factors due to the orbital interactions.

Keywords

• electron paramagnetic resonance
• nuclear magnetic resonance
• Knight Shift
• ⁶³Cu
• YBa₂Cu₃O₇