Theoretical studies of the spin-Hamiltonian parameters and defect structure for the tetragonal Gd³⁺ center in cubic c-RbZnF₃ crystal

Abstract

A diagonalization (of the energy matrix for which the Hamiltonian contains the free ion, crystal-field interaction and Zeeman interaction terms) method was applied to calculate the spin-Hamiltonian parameters (g factors, g _// and , and five zero-field splittings, ) for the tetragonal Gd³⁺ center in cubic c-RbZnF₃ perovskite. The calculated results are in reasonable agreement with experimental values. From the calculation, the defect model that the tetragonal Gd³⁺ center is attributed to Gd³⁺ occupying the 12-fold coordinated Rb⁺ site associated with a nearest Rb⁺ vacancy, V_Rb, along C ₄ axis owing to charge compensation is confirmed and the defect structural data of this Gd³⁺ impurity center in c-RbZnF₃ are acquired. The results are discussed.

Keywords:

• crystal field
• defect structure
• electron paramagnetic resonance
• c-RbZnF₃
• Gd³⁺

Acknowledgements

This work was supported by ICMP, CAS, Grant No. ICMP 2009001.