Structural-Phase State and Magnetotransport Properties of Thin Film Alloys Based on Permalloy and Copper

Автор(ы) I.O. Shpetnyi1, K.V. Tyschenko1, V.Ya. Pak1, B. V. Duzhyi2, Yu.O. Shkurdoda1, I.Yu. Protsenko1
Принадлежность

1Sumy State University, 2, Rimsky-Korsakov St, 40007 Sumy, Ukraine

2National Aerospace University "Kharkiv Aviation Institute", 17, Chkalov St, 61070 Kharkiv, Ukraine

Е-mail i.shpetnyi@aph.sumdu.edu.ua
Выпуск Том 13, Год 2021, Номер 1
Даты Received 03 January 2021; revised manuscript received 15 February 2021; published online 25 February 2021
Ссылка I.O. Shpetnyi, K.V. Tyschenko, V.Ya. Pak, et al., J. Nano- Electron. Phys. 13 No 1, 01020 (2021)
DOI https://doi.org/10.21272/jnep.13(1).01020
PACS Number(s) 61.05.J –, 61.72. – y, 75.47.De, 81.40.Gh
Ключевые слова GMR effect, Granular state, Spin-dependent scattering, Permalloy, Superparamagnetism.
Аннотация

The paper presents the results of research influence of composition on structural-phase state and magnetoresistive properties of as-deposited and heat-treated at temperatures Ta ≤ 900К samples film alloys based on Py and Cu. Samples of thin film alloys with a thickness of d = 25 nm in the range of 19 ≤ cCu ≤ 69 (where cCu is the concentration of Cu, at.%) were obtained by the method of co-evaporation in vacuum from two independent evaporators. The structural-phase state of the samples of film alloys at cCu = 19 at.%, 34 at.% and 61 at.% was investigated by the method of transmission electron microscopy. The structure of thin films in both as-deposited and annealed at Ta ≤ 900 K state consists of quasi granules with permalloy embedded in a nonmagnetic Cu matrix. The phase state of the samples at cCu = 19 at.% and cCu = 34 at.% in the as-deposited state and after heat treatment at Ta = 600 K corresponded to fcc-NixFe (x ≈ 3) + fcc-Cu. After heat treatment at temperatures of 700 ≤ Ta ≤ 900 К, the phase state of the samples at cCu = 19 at.% and cCu = 34 at.% corresponded to Ni3Fe + fcc-Cu. For the film alloy sample at cCu = 61 at.% in the as-deposited state and after heat treatment at temperatures of 600 ≤ Ta ≤ 900 К, the phase state corresponded to fcc-NixFe (x ≈ 3) + fcc-Cu. Studies of the magnetoresistive properties of film samples showed that the film samples in the entire range of compositions of 19 ≤ cCu ≤ 69 at.% were characterized by isotropic magnetoresistance. The maximum value of the giant magnetoresistance was observed for the sample with cCu = 34 at.% Both in the as-deposited state and after heat treatment at temperatures of 600 ≤ Ta ≤ 900 К. Heat treatment of samples in the temperature range of 600 ≤ Ta ≤ 900 К had almost no effect on the value of GMR films at 19 ≤ cCu ≤ 51 at.%.

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