Determination of the local structure of the superconducting compound Y Ba(sub 2)Cu(sub 3)O(sub 7-y) from the EPR spectrum

摘要

The EPR spectrum has been observed for Cu(sup 2+) ions in the high Tc superconductor Y Ba(sub 2)Cu(sub 3)O(sub 7-y). The g-factors have been found to be 2.0023 (+-) 0.0005 and 2.255 (+-) 0.005 for g(sub parallel), 2.054 (+-) 0.005 and 2.194 (+-) 0.005 for g(sub perpendicular). The relationships are established between the g-factors and the local structure parameters in the framework of crystal field theory, with the use of the d-orbital model proposed by Zhao et al. The values R = 195A and (theta) = 97 deg. are deduced for the C(sub 4(nu)) site and R = 1.84A for the C(sub (infinity)) site. The results are compared with those published previously by means of x-ray and neutron diffraction experiments. (author). 29 refs, 1 fig., 1 tab. (Atomindex citation 26:039746)