A STRING MAGNETOMETER USING THE METHOD OF SMALL PERTURBATIONS

Abstract

Subject and Purpose. The existing interest in nanosized magnetic materials requires equipment for express post-synthesis measurements of magnetic properties of these nanostructures in such a way as to exclude any mechanical displacement of the sample. Although there exist plenty of methods and devices for studying magnetic properties of materials, the development of novel schemes based on the known techniques for examining properties of magnetic nanomaterials, for example magnetic nanopowders, is a hot problem. Th e measurement equipment of the sort will detect changes in the magnetic properties of materials over time and under the infl uence of various factors, such as temperature, external magnetic fi elds, stabilizing substances. Method and Methodology. The developed setup for registering magnetic hysteresis loops is based on the method of small perturbations performed by an alternating magnetic fi eld. The devised scheme combines conventional physical principles of both hysterometers and vibrating-sample magnetometers. Results. With the aid of the developed setup, magnetic hysteresis loops of La 0.775 Sr 0.225 MnO3 nanopowder have been obtained and compared with the data provided by the well-known technique. A good agreement was observed. Th e measurement error was 10%. Conclusion. The suggested scheme can be used for the express registration of magnetic hysteresis loops of miscellaneous magnetic materials of various compositions, including nanoscale magnets.