DOI: https://doi.org/10.30970/jps.23.2701
MAGNETIC PROPERTIES OF Gd-Fe FILMS
V. Prysyazhnyuk, O. Mykolaychuk
Faculty of Physics, Ivan Franko National University of Lviv,
8a, Kyrylo and Mefodiy St, Lviv, UA-79005, Ukraine
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Journal of Physical Studies 23(2), Article 2701 [3 pages] (2019)
DOI: https://doi.org/10.30970/jps.23.2701 MAGNETIC PROPERTIES OF Gd-Fe FILMSV. Prysyazhnyuk, O. Mykolaychuk
Faculty of Physics, Ivan Franko National University of Lviv, |
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Using the method of thermal evaporation on fluoroplastic substrates, amorphous films of the compounds of Gd-Fe system have been produced. The substrate carrier temperature was 293\,К. The increase in temperature of substrates or annealing of films carrier leads to the increase in amount of a polycrystal phase. The width of the films was 200 nanometers. The checkout of the structure of the films was done by the electron microscope UEMV-100\,K with the use of high-temperature prefix PRON-2. Magnetic examinations were done by a vibrational magnetometer. The field magnetisation vector was parallel to the film plane. The peak saturating field is 300\,KA/m.
Magnetic hysteresis loops have been obtained by small operation of an external field on magnetisation reversal.
The value of coercive force has been measured. The value of coercive force decreases with the formation of an amorphous film in comparison with bulk samples. The reason for the decrease is the lack of the long-range order in amorphous materials. This in turn leads to a decrease of magnetic anisotropy, which influences the magnitude of the coercive field. The formation of the polycrystal phase in the films leads to an increase in magnetic hardness. The value of magnetic hardness in polycrystal films exceeds that in bulk samples. This can be explained by the fact that we measured the magnetisation of the films along a surface. It is known that in films there are flat domains. Such domains are much easier to magnetise along a surface than perpendicularly to a surface. We have also noticed that for value of a coercive force, it does not matter how the film crystallises. We used two methods of crystallisation. The first method is the formation of a polycrystal film on a warmed-up substrate. The second method is the crystallisation of amorphous films by their annealing.
The temperature dependences of magnetic saturation have been obtained and the Curie temperature for bulk samples and films GdFe$_2$ and Gd$_2$Fe$_{17}$ has been found. It is proved that the structural disorder leads to a depression of the Curie temperature and the degree of magnetic saturation.
PACS number(s): 75.70.-i