Nanocomposites and nanomaterials

Magneto-optical properties of bilayer film systems based on Fe and Pt

Bezdidko O., Shkurdoda Yu.O., Shabelnyk Yu. M., Protsenko S.I., 
Tkach O.P., Kosenko O.S.
 Sumy State University, Electronics, General and Applied Physics Department, 
2, R.-Korsakov st., 40007, Sumy, Ukraine
E-mail: o.bezdidko@aph.sumdu.edu.ua

The formation of film structures with given characteristics is one of the pressing issues of solid state physics. The main magnetic and magneto-optical characteristics are: high values ​​of magnetoresistance, saturation induction, sensitivity to changes in the external magnetic field, as well as their stability when exposed to external factors, such as temperature. The study of the magneto-optical Kerr effect is one of the methods for determining the above parameters and the magnetic state of film systems, as well as an indirect method for studying the structural-phase state, which, as is known, significantly affects the magnetic and magneto-optical parameters of film instrument structures. By changing the shape of the hysteresis loop, we can conclude that the phase state of the system changes: the formation of a solid solution, the formation of a granular state, blurring of interfaces. Multilayer film systems and multilayers based on Fe and Pt were obtained at ultrahigh vacuum in a Caburn MDC Europe vacuum chamber, located at the Institute of Physics, University of. J. Gutenberg in Mainz (Germany).
It was found that both in the case of single-layer iron films of different thicknesses (12 - 42 nm), as well as in the case of bilayer (Fe/Pt) and multilayers [Fe(3)/Pt(3)]2-8, an increase in the saturation magnetization and residual magnetization with increasing film thickness is observed. For the single layer Fe HS  linearly increases from 3,255 to 3,287, Fe(22)/Pt(3-15) – 3,261 to 3,276, Fe(12-32)/Pt(9) – 3,267 to 3,275,  [Fe(3)/Pt(3)]2-8 –  3,263 to 3,277 (abr. units).
In the case of single-layer Fe films, the coercivity increases with a thickness in the range from 2.5 to 4.5 Oe, which is still an extremely small value. With a constant value of the Pt thickness, coercivity likewise increases with an increase in the thickness of the iron layer (2,8 to 3,0 Oe), and accordingly decreases, with an increase in the concentration of the nonmagnetic component (3,4 to 2,6 Oe). An interesting result is for the Fe(3)/Pt(3) multilayers with the number of repeatable elements from 2 to 8. For these multilayers, an increase in the main magnetic parameters is observed compared with bilayer films at the same effective thickness.
This work was supported by the Ministry of Education and Science of Ukraine (Grant №0117U003925).