An automated setup for studying thin ferroelectric films by the thermal-noise method

Abstract

Determination of the initial permittivity (the permittivity in a weak electric field—a field that is much lower than the coercive field) of thin ferroelectric films is the most important problem in studying such objects. For this purpose, the thermal-noise method is a convenient tool. In this case, in contrast to the bridge method, a measuring voltage that can create a significant field in a sample is not applied to it, but a thermalnoise voltage that depends on the film capacitance is measured across a load resistor, which is connected in parallel to the specimen. Below, an automated setup using the LabVIEW package is described. The technique was first applied to studying thin films. A significant difference between the results of measuring the permittivity of thin films by the bridge and thermal-noise methods has been revealed.