高温超导材料的电子顺磁共振理论研究

Theoretical investigations of electron paramagnetic resonance parameters for the high T_c superconductor materials

为了合理解释含稀土离子的高温超导材料的电子顺磁共振谱,从晶体场理论出发,给出晶体材料中稀土离子的微扰公式,阐述了高温超导材料中稀土Kramers离子的自旋哈密顿参量理论,并计算给出了稀土离子Re3+的电子顺磁共振(electron paramagnetie resonance,EPR)参量g因子和超精细结构常数A。计算结果与实验谱线符合较好,说明所采用的微扰公式和理论处理方法是有效和合理的。研究表明,对高温超导材料中Re3+的自旋哈密顿参量进行精确解释,通常应该考虑到二阶微扰项的贡献。

In order to explain the electron paramagnetic resonance spectra of high-Tc superconductor materials doped with rare-earth ions reasonably,based on the crystal-field theory,the second-order perturbation formulas are deduced and the spin Hamiltonian parameters for the Kramers Re3＋ ion have been studied in this paper.And the EPR parameters g factors and hyperfine structure constants are calculated.The calculated results are in reasonable agreement with the observed values.It shows that the perturbation formulas and the computing methods are effective and reasonable.The results also show that for interpreting the SH parameters of Re3＋ in high-Tc superconductors more effectively,the contribution of the second-order perturbation terms should be considered.