Deformation and stress relaxation of single crystal BaTiO₃

Abstract

Deformation and stress relaxation tests were carried out on BaTiO₃ single crystals at room temperature with a view to study the behaviour of 90° domain walls under uniaxial compression. The stress: strain curves obtained under constant strain rate were found to consist of three distinct regions. The first two regions were associated with 90° wall movements and the third region with the elastic deformation of the crystal. Stress relaxation was observed in the first two regions but not in the third. The nature of variation of stress strain curves and the stress relaxation behaviour was studied as a function of increasing fraction of one of the twin or domain components. High strain rate tests show kinks in the stress strain curves similar to the Barkhausen pulses in electrical experiments.