Laboratory of Magnetodynamics
In 1986, according to the decision of the Institute Scientific Council, the Department of Magnetodynamics was founded, reorganized later into the Laboratory of Magnetodynamics. The organizer and the first head of the Department, and then of the Laboratory, was Doctor of Phys. and Math. Sciences, Professor Petr Kim, who had been working in this position for more than fifteen years. Now the Laboratory is headed by Doctor of Phys. and Math. Sciences, Professor Gennady Patrin
For many years the main direction of the Laboratory research was the development of physical basis and technology of materials for use as magnetic recording media. The world-level results were obtained in this field, namely, the nanocrystal film material (Co80Ni20)1-xNx was developed and the hard magnetic disc for high-density recording was created on its basis. Intensive studies of dynamics of domain walls both in films and in single crystals were carried out. The resonance of domain wall intrinsic structure (Bloch lines) was discovered and investigated. The method of magnetooptical detection of forced oscillations of domain walls was developed.
Currently, the basic area of the Laboratory activity is the development and investigation of multilayer magnetic structures for spintronic devices. In terms of development of physical basis of materials possessing of spin-dependent electron transport, multilayer magnetic films transition metal/semiconductor are being studied. Here a number of priority results have been obtained, namely:
- existence of temperature dependent exchange in films with a semiconductor spacer has been shown;
- photoinduced modification of interlayer exchange has been discovered;
- interlayer exchange dependence on magnetic field and ferromagnetic layer thickness has been found;
- spin-glass behavior of magnetization in weak magnetic fields has been revealed.
For the first time, (Tb, Dy-Fe, Co)/NiFe bilayer films with orthogonal orientation of magnetization easy axes in layers possessing of unidirectional magnetic anisotropy of the exchange character and promising for application in spin-valve devices have been fabricated. On the basis of multicomponent oxide compounds and rare earth/3d-metal alloys the materials for magnetooptical devices are being developed. In particular, basing on Bi1.7Y1.3Ga1.8Fe3.2O12 and CrCoFeO4 ferrooxides, polycrystal films with high magnetic and magnetooptical parameters have been made. First the recoding of magnetooptical information in a hard layer of (Tb, Dy-Fe, Co)/NiFe film systems by optical pulses has been realized by using the energy of exchange interaction with a NiFe layer, that allow to reduce economic expenses on the processes of information recoding and erasing in more than two orders of magnitude.
The new mechanism of optical recording of magnetooptical information at temperatures much less than the Curie temperature has been found, where the main contribution to the recording process is made by the magnetoelastic interaction of magnetostrictive films of rare earth and transition metals. This recoding mechanism has been named the thermoelastic magnetic mechanism.
Research works in the field of development of materials based on CoPt, CoPd, FePt and Fe-Pd magnetic alloys with perpendicular magnetic anisotropy for ultrahigh-density magnetic recording are being actively continued. On the basis of the nuclear echo formation method developed by the Laboratory researchers, investigations of magnetic structure of multilayer films and single crystal materials are being carried out.
The main scientific results obtained are reported in the following publications:
- Kim P.D., Turpanov I.A., Brushtunov Ì.Ì., Khvan Do Chen, Baksheev N.V. Magnetic disk. Certificate of Authorship ¹ 1631569, G 11 B 5/66 SU (1990).
- Kim P.D., Turpanov I.A., Stolyar S.V. et al. Perpendicular magnetic anisotropy in Co50Pt50/MgO(100) single crystal films. ZhTF, 2004, v.74, issue 4, pp.53-57.
- Seredkin V.A., Burkova L.V, Erukhimov M.Sh., Frolov G.I, Yakovchuk V.Yu. Thermomagnetic recording of analog information in R – Fe (R – Tb,Fe) films. ZhTF, 1985, v.55, issue .4, Ñ.707-713.
- Lepeshev À.À., Polyakova K.P., Seredkin V.A., Pavlov V.À. Polycrystal films of Bi-substituted yttrium ferrogarnet: obtaining and properties. Autometrya, 1995, ¹ 3, pp.50-57.
- Patrin G.S, Vas’kovsky V.Î., Svalov À.V., Eryemin Å.V., Panova Ì.À., Vasilyev V.N. Magnetic resonance in multilayer magnetic films of the Gd/Si/Co system. ZhETF, 2005, v.127, issue 6, Ñ.74-81.