材料期刊网

The g factors g (parallel to) and g (vertical bar) of the isolated tetragonal Cu(II)O-5 cluster in YBa2Cu3O7-delta superconductors induced and suppressed by mechanical processing are calculated from the complete diagonalization (of the energy matrix) method (CDM) and the perturbation theory method (PTM). Both methods are based on the cluster approach where in addition to the contribution of the spin-orbit parameter of the central metal ion, the contribution of ligand ion via the covalence effect is taken into account. In the calculations, the structural data of the Cu(II)O-5 cluster gained from x-ray diffraction are applied. The results from both the CDM and the PTM are similar and show reasonable agreement with the experimental values. It appears that both methods can be used to explain the EPR g factors for d(9) ions in crystals.