HiSORセミナー
Epitaxial nanofilms for oxide spintronics
日時 2019年3月6日 （水） 13:00-
場所 放射光科学研究センター 2階 セミナー室
講師 Nikolai Sokolov
(Ioffe Institute of Russian Academy of Sciences)
Wide microwave and magneto-optical applications of ferrites are well-known [1,2]. Among broad family of ferrites, yttrium iron garnet (YIG, Y3Fe5O12) is the most famous because of its unique properties as ultra-low damping of spin waves [3] and very useful for applications magneto-optical properties [4]. However YIG applications in high frequency devices is limited by 1-2 GHz because of relatively low saturation magnetization and magnetic anisotropy. For higher frequency applications (up to 10 GHz), ferrites with spinel type structure are attractive, among them nickel ferrite (NFO, NiFe2O4) is the most studied.
There is extensive experience of studies of YIG and NFO bulk crystals and micron thick epitaxial films grown by liquid phase epitaxy LPE [5]. However recent decades large interest in fabrication and studies of nanometer thin ferrite films has appeared. It is due to not only general trend for device miniaturization but also possibilities to use strain engineering to control thin film magnetic properties [6] and potential application in spintronics, including just a few nanometer thin ferrite films in spin filtering devices, see for recent reviews [7-9].
In my talk, first I will discuss in short main properties of bulk YIG and NFO crystals. Then I will review some recent studies of garnet and spinel nanometer size epitaxial films carried out by other research groups. At last, I will present recent experiments on YIG and NFO nanolayers grown by Laser Molecular Beam Epitaxy and studied in our group with use of the international collaboration opportunities.
[1] A. Paoletti, Physics of Magnetic Garnets (North-Holland, Amsterdam, 1978)
[2] A. H. Eshenfelder, Magnetic Bubble Technology (Springer, New York, 1981)
[3] Le Craw, et al. Physical Review, 110(6), 1311-1313 (1958)
[4] Paroli, P. Thin Solid Films, 114(1-2), 187-219 (1984)
[5] Robertson, J. M. Journal of Crystal Growth, 45(C), 233-242 (1978)
[6] Kubota M., et al. Journal of Magnetism and Magnetic Materials, 339, 63-70 (2013)
[7] Harris, V. G., et al. Journal of Magnetism and Magnetic Materials, 321(14), 2035-2047 (2009)
[8] Moussy, J.-B. Journal of Physics D: Applied Physics, 46(14), 143001 (2013)
[9] Chumak, A. V., et al. Nature Physics, 11(6), 453-461 (2015)
問合せ先 沢田正博（放射光科学研究センター）
