Electron Spin Resonance of Fe³⁺ in BaTiO₃ in the Rhombohedral and the Cubic Phases.

Abstract

Additional studies of the electron spin resonance have been made for Fe 3+ in BaTiO 3 in the rhombohedral and the cubic phases. Spin Hamiltonian parameters in the rhombohedral phase were determined by the measurement of the specimen converted into single domain by biasing it upon cooling. Parameters have been obtained as α- F =0.0113±0.001 cm -1 , D =-0.0023±0.0005 cm -1 . Behavior of orientation-dependent line widths was observed and was related to the mechanism of the random internal strain. A part of weak lines at lower magnetic field was interpreted as `forbidden' transitions corresponding to Δ M >1. Transition probabilities were computed and compared with observed intensities. Some comments are offered as to the ESR study of the ferroelectric phenomenon just above the Curie temperature.