Zero-Field Splitting of-State Ions. I. Point-Multipole Model
- 9 September 1966
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 149 (1), 257-269
- https://doi.org/10.1103/physrev.149.257
Abstract
The zero-field splitting terms in the spin Hamiltonian for an -state ion, and , are computed using a point-multipole model. Various contributions to and are considered and quantitative results are given for the most important mechanisms. Specific application is made to : Zn and Mn, where accurate values for and are known from electron-spin-resonance experiments. The most important contribution for these cases comes from the "Blume-Orbach" mechanism involving the first-order matrix element of the axial and rhombic fields between excited quartet states which have been admixed into one another by the cubic component of the crystalline field. This term contributes results of the correct sign, and of nearly the correct magnitude, to explain the entirety of the axial and rhombic field splitting of in these hosts. The next most important contribution arises from the spin-spin interaction (the "Pryce" mechanism) involving again the first-order matrix element of the crystalline field, but this time between an excited configuration and the ground state. Instead of the usual perturbation approach, the Schrödinger equation containing the crystal-field potential is integrated numerically. It is found that the term considered by Pryce, the admixture, is small, and of the opposite sign from the more important contribution of the admixture. The net contribution from the spin-spin mechanism yields results for of the wrong sign and of roughly one-third the magnitude of the Blume-Orbach term, and for a constribution of the correct sign but an order of magnitude smaller than the Blume-Orbach term. The configuration-interaction contribution of Orbach, Das, and Sharma is shown to be next in decreasing order of importance, followed by the contribution originally computed by Watanabe.
Keywords
This publication has 26 references indexed in Scilit:
- Effect of Uniaxial Stresses on the Paramagnetic Spectra ofandin MgOPhysical Review B, 1964
- Spin-Lattice Interaction of a Mn++Ion in MgOProgress of Theoretical Physics, 1962
- Spin-Lattice Relaxation of-State Ions:in a Cubic EnvironmentPhysical Review B, 1962
- Iron Series Hartree-Fock CalculationsPhysical Review B, 1960
- Electron Spin Resonance of Mn++Ion in Ionic CrystalsProgress of Theoretical Physics, 1960
- Antishielding of Nuclear Quadrupole Moments in Heavy IonsPhysical Review B, 1958
- On the Ground Level Splitting of Mn++and Fe+++in Nearly Cubic Crystalline FieldProgress of Theoretical Physics, 1957
- Variational Approach to the Quadrupole Polarizability of IonsPhysical Review B, 1956
- Spin-Spin Interaction within Paramagnetic IonsPhysical Review B, 1950
- LXXXIII.The theory of the paramagnetic rotation and susceptibility in manganous and ferric saltsJournal of Computers in Education, 1934