“Smart” materials are now increasingly being used in energetics, medicine, biology, etc. Such materials include compounds with a magnetocaloric effect which means that their temperature changes when the external magnetic field is applied to them. Today, these compounds are actively researched as a promising basis for various applications: from the environmentally safe freon-free refrigerator to “smart” implants with controlled drug release.
At the same time, the research methods for these materials are being improved and developed. One of the important tasks in this direction is the development of non-contact methods of studying the magnetocaloric effect. These are necessary when it is technically impossible to use standard contact temperature meters – thermometer or thermocouple. This is particularly relevant for the investigation of the magnetocaloric effect in micro- and nano-scale objects.
IKBFU Researchers worked jointly with colleagues from the University of Parma (Italy) and Dresden High Magnetic Field Laboratory Helmholtz-Zentrum Dresden-Rossendorf (Germany). The scientists used a new non-contact method to carry out joint research on a perspective magnetocaloric alloy introduced earlier by the Italian colleagues. (https://aip.scitation.org/doi/10.1063/1.4939451).
Francesco Cugini, Postdoctoral Fellow at the University of Parma, Italy, said “Our non-contact temperature measurement method is based on a thermo-optical effect known as the “mirage effect” and consists of the deviation of a laser beam passing through a surface close to the object due to temperature changes in the sample. The mirage effect is also observed in nature as an optical phenomenon in the atmosphere: the refraction of light at the boundary between dramatically different air layers in terms of density and temperature.”
“Thermo-optical effects are actively used in modern research, particularly in photothermal spectroscopy, and our approach in using it for the study of magnetocaloric materials is undoubtedly new”.
Karim Amirov, Senior Researcher at the IKBFU Laboratory of Novel Magnet Materials, said “The main idea of our research was to measure the magnetocaloric effect using three independent methods: non-contact, direct using a thermocouple, and indirect using thermodynamic relations. A promising iron-rhodium alloy, which we studied quite well, was chosen as an object of investigation. It is important that the method we have proposed can be successfully implemented to study the “smart” composite materials and alloys we obtain – from massive samples to tapes and films.”
“The results obtained using the non-contact method do not contradict the results obtained using classical methods. Thus, we have shown that an alternative non-contact temperature measurement method can be successfully applied to our applications”.
The research results were published in “Journal of Applied Physics” Scientific Journal
The project was supported by the Russian Science Foundation grant.