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Pseudocubic Angular Dependence of the M = −1/2 to +1/2 EPR Transitions for Ions with S = 3/2 by Small Distortions of the Cubic Crystal Field
Author(s) -
Gehlhoff W.
Publication year - 1977
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220800216
Subject(s) - electron paramagnetic resonance , ion , crystal (programming language) , hamiltonian (control theory) , cubic crystal system , condensed matter physics , physics , principal axis theorem , perturbation (astronomy) , field (mathematics) , microwave , chemistry , atomic physics , quantum mechanics , mathematics , geometry , mathematical optimization , computer science , pure mathematics , programming language
The line positions of the EPR transitions — determined by the generalized spin Hamiltonian ℋ = gβ BS + ∫β{ S x 3B x + S y 3B y + S z 3B z − 1/5 ( SB ) [3 S ( S + 1) − 1]} for cubic symmetry and S = 3/2 — are calculated to the second order of perturbation theory taking into account small rhombic distortions of the crystal field. In the case of the transition M = −1/2 ⟷ +1/2 — frequently the only one experimentally observed — it is shown that under certain conditions such distortions of the crystal field apparently cause the same cubic angular dependence as the term ∫β S 3 B does. Therefore, the parameters f and g determined from the experiment may contain contributions of non‐cubic fields. These contributions, which can be determined by measuring at two microwave frequencies, are calculated for four different systems of the rhombic principal axes.