English (UK)
Project on the BRFFR 'Study on magnetic domain dynamics of magnetocalorimetric thin film materials'

Scientific research (R&D) of the SSPA "Scientific-Practical Materials Research Centre of NAS of Belarus" and Belarusian Republican Foundation for Fundamental Research (BRFFR) based on the Bureau of the Scientific Council of 25 October 2012 protocol № 6. The joint project performed research team Division of Cryogenic Research SSPA "Scientific-Practical Materials Research Centre of NAS of Belarus" and Chungbuk National University (South Korea), in accordance with the contract number BRFFR F12KOR-004. Scientific study on the "Study on magnetic domain dynamics of magnetocalorimetric thin film materials".

The initial term of the work on the subject of the contract - November 1, 2012, deadline for the job - October 31, 2014

The purpose of the work: the establishment of the relationship of magnetic, magnetotransport and magneto-optical properties to the dynamics of domain walls. Also supplied to determine the impact of these processes on magnetocalorimetric effect, through the development of methods for the synthesis of metal oxide films of barium strontium compounds ferromolibdata (Sr2-xBaxFeMoO6-δ) with controlled defects in the anion and cation subsystems.

The main scientific idea of ​​the project is that the synthesized films of variable composition Sr2-xBaxFeMoO6-δ with a high degree of spin polarization and controlled by magnetic and magnetoresistive properties can have a high mobility of the magnetic domains, which will achieve maximum of magnetocalorimetric effect.

Scientific and practical groundwork: by the Belarusian participants of the project research team of the Division of Cryogenic Research SSPA "Scientific-Practical Materials Research Centre of NAS of Belarus" has experience in various fields of materials science and solid state physics. In particular, the project has developed an original method beztigelny controlled crystallization of single crystals of high-temperature superconductors, the method of heat treatment of oxygen textured and single crystal cuprate allowing purposefully change the concentration and anion ordering defects electrotransport adjusting the properties of materials. Currently active in research on the development of magnetic field sensors based on directional heterostructures Sr2FeMoO6-δ / insulator / Sr2FeMoO6-δ. When optimizing the synthesis conditions, a single-phase connection Sr2FeMoO6-δ with the desired physical properties, the following sequence of phase transitions in the systems Fe2O3-MoO3-SrCO3 and SrMoO4-y-SrFeO3-x in the formation of strontium ferromolibdata [N. Kalanda, S. Demyanov, W. Masselink, et al. Cryst. Res. Technol. 46, 463 (2011); M.Kalanda, G.Suchaneck, A.Saad, et al. Materials Science Forum, 636, 338 (2010)]. For the first time for the synthesis of solid-phase target Sr2FeMoO6-δ with low resistivity values ​​were used and fine-grained connection SrFeO2.52 and SrMoO3 [N.A.Kalanda, N.N.Krupa, patent number 13,073. Request number a20080868].
The universal measuring system company "Cryogenic Limited", by which it is possible to make measurements in the temperature range 4.2 - 300 K and in magnetic fields up to 14 T, the analysis of the magnetic state of the samples Sr2FeMoO6-δ depending on the synthesis conditions [H . A.Kalanda, S.E.Demyanov, L. Kovalev, Low Temperature Physics 37, 1057 (2011)]. On the basis of the research team gained experience management parameters such as the Curie temperature, the coercive force, the magnetization required to use double perovskite ferromolibdata strontium as a work item in the magnetic field sensor. The need to study the magnetotransport properties of the compound Sr2FeMoO6-δ team has developed an universal automated system "GONIOM" for low-temperature measurements of material properties at high magnetic fields, which allows to measure electrical and galvanomagnetic properties of materials with different types of conductivity (metal, semiconductor) in magnetic fields up to 8.5 T in the temperature range 4.2 - 50K.
Korean participants by the project research team of the Faculty of Physics Chungbuk National University, has extensive experience in studies of magnetic materials of complex metal oxides. Currently research group conducts research magnetocalorimetric effect in various materials, including the structure of the double perovskite [G. J Liu, J. R. Sun, J. Shen, B. Gao, H. W. Zhang, F. X. Hu, B.G.Shen, Appl. Phys. Lett. 90, 032507 (2007)]. These materials magnetocalorimetric effect is studied as a function of cation composition and modes of synthesis of materials. In this regard, the use of ion-beam sputtering method and a SQUID magnetometer and low temperature with a vibrating magnetometer probe possible to optimize the conditions for obtaining thin-film samples Sr2FeMoO6 with high magnetization and magnetocalorimetric effect. In addition, the researchers were able to achieve high values ​​of the magnetic entropy ΔSM ~ 0.38 J/kg in bulk samples and Ba2-xLaxFeMoO6 ΔSM ~ 0.98-1.93 J/kg of bulk samples Ba2FeMoO6 at temperatures T ~ 320-330K, which is important to terms of its applications [K. S. Kim, M. S. Lee, Y. D. Zhang J. Appl. Phys. 111, 07A947 (2012); K. I. Kim, M.S.Lee, S.C.Yu, et al. Journals & Magazine 47, 2474 (2011)]. Korean scientists also have the option of direct observation of magnetic domain structures in various thin magnetic films, bulk samples and nanoparticles [H.-G. Piao, D. Djuhana, J.-H. Shim, S.-H. Lee, S.-C. Yu, S. K. Oh, S.-M.Ahn, S.-B. Choe, D.-H. Kim, J. Nanosci. Nanotech. 11, 6122 (2011); J.-H. Shim, H.-G.Piao, S.-H.Lee, SKOh, S.-C.Yu, SKHan, D.-H. Kim, Appl. Phys. Lett. 99, 142505 (2011)]. Using computer simulations and Monte Carlo effects micromagnetic processes in ferromagnetic systems, they were able to predict the dynamics of magnetic domain walls, depending on the substrate material and the point defects in the film structures of double perovskites [J.-H.Shim, S.-H.Jun , SKOh, S.-C.Yu, D.-H.Kim, Sae Mulli 60, 663 (2010)].

Information about organizer of the programme:
Belarusian Republican Foundation for Fundamental Research http://fond.bas-net.by/default_eng.html



Areas of work