Studies on the g factors of tetragonal Cu2+ sites in NdBa2Cu3Ox and Nd0.05Y0.95Ba2Cu3O6

The anisotropic g factors are theoretically studied for the Cu2+(2) sites in NdBa2Cu3Ox and Nd0.05Y0.95Ba2Cu3O6 from the perturbation formulas of the g factors for a 3d(9) ion in tetragonally elongated octahedra. The local low symmetrical (tetragonal) distortions of the five- fold coordinated Cu2+ (2) sites are quantitatively correlated to the electron paramagnetic resonance (EPR) analysis in terms of the tetragonal field parameters based on the superposition model, and the ligand contributions are included in view of obvious covalency. The possibility of the above EPR signals arising from Nd3+ may be excluded for both systems.