FIELD: physics.
SUBSTANCE: invention relates to nondestructive methods of controlling state of material. The method of determining electret properties of mica involves thermostating a sample of analysed material at temperature not exceeding melting temperature. An electric field is applied to the sample and polarisation is done for a period of time longer than relaxation time at the given temperature. After this without switching off the electric field, the sample is cooled to temperature at which thermo-activation processes in the material virtually stop. Electric field is then switched off and the sample is linearly heated to temperature above polarisation temperature and thermal insulated depolarisation current of the sample is measured. Only the last high-temperature peak, resulting from formation of spatial charge, is analysed. The shape of the right side of this peak is determined and, if after turning over the sample and repeated recording of the spectrum of thermal insulated depolarisation current, the shape of the right side of the peak changes, i.e. moves up as a result of superimposition of electret thermo-depolarisation current, then the given material is an electret.
EFFECT: invention can allow for controlling quality of electrets in operational conditions, during their manufacturing process, as well as in making super-thin insulating materials and nanofilms for microchips and other electric devices, which use electrets.
3 dwg
