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Information × Registration Number 0217U006731, 0117U003590 , R & D reports Title Superconductor nanocomposites - ferromagnetic semi-metal as the newest functional materials for microwave radiation registration popup.stage_title Head Tarenkov Vladimir Yuriyevich, Registration Date 18-12-2017 Organization Donetsk Institute of Physics @ Engineering named after O.O.Galkin NAS of Ukraine popup.description2 Objects of research: nanocomposites from the superconductor of magnesium diboride MgB2 and nanosized particles of lanthanum manganites La0.7 Ca0.3 MnO3 or La0.7 Sr0.3 MnO3. The critical temperature of the superconducting transition of magnesium diboride is TC = 39 K; Curie temperature of manganite nanoparticles 280-320 K; the MgB2 particles were 5-10 ?m in size, and La0.7 Ca0.3 MnO3, La0.7 Sr0.3 MnO3 - 20-30 nm. In nanocomposites at the percolation threshold of the superconducting component MgB2 (about 80 volume percent), a net of contacts arises and below the superconducting transition temperature a system of weak superconductor-magnet-superconductor bonds is formed. The presence of magnetic inclusions (manganite) makes the current characteristics of the nanocomposite sensitive to magnetic fields. At the same time, the critical parameters of the structure remain sensitive to alternating electromagnetic fields. The spread of the electrical resistivity indices was not more than 5%, which indicates a good homogeneity of the composite. Electron microscopy with the help of a scanning microscope made it possible to determine the dimensions of the granules of the ceramic material, as well as the elemental composition of the compounds forming the composite. Research methods: Transport characteristics were measured on a complex with the recording of the temperature dependences of the resistance, current-voltage characteristics (VAC), and the effect of magnetic fields on these dependences over a wide temperature range was also established. Experiments have been carried out on the effect of high-frequency electromagnetic radiation on the width of the superconducting transition and the VAC of a nanocomposite, both in the absence of a magnetic field and in magnetic fields. The characteristics of the nanocomposite demonstrated a high sensitivity to external high-frequency radiation, which were also preserved in external magnetic fields. The results of the studies indicate the realization in superconductor-manganite superconducting nanocomposites of a superconducting loosely bound medium that is stable to the action of an external static magnetic field and sensitive to external high-frequency radiation. Product Description popup.authors Білоголовський Михайло Олександрович Болясова Ольга Олександрівна Криворучко Володимир Миколайович popup.nrat_date 2020-04-02 Close