Reversible domain switching in ferroelectric triglycine sulphate (TGS) by Laser

Abstract

It is known1 that laser pulses can lead to reversible domain switching in ferroelectric TGS. A tentative explanation in terms of a depolarizing electric field issued from bound charges due to thermal shock was proposed.2Experiments are now given showing that a slow quasistatic illumination leads to the same reversible domain switching. In this case the electric field inside the crystal is easier to calculate. In a rough approximation assuming known values of pyroelectric coefficient, thermal conductivity and dielectric constant, it is shown that close to the surface the electric field is parallel to the spontaneous polarization. Inside the crystal it is opposed to it with values of the same order of magnitude as the coercive field at room temperature measured by classical methods. It is thus demonstrated that such a field is really responsible for the domain switching.The pyroelectric probe technique is used to inspect the surface opposite to a fixed illuminating spot and has shown the end of a domain whi...