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

Authors I.O. Shpetnyi1, K.V. Tyschenko1 , V.Ya. Pak1, B. V. Duzhyi2, Yu.O. Shkurdoda1, I.Yu. Protsenko1
Affiliations

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
Issue Volume 13, Year 2021, Number 1
Dates Received 03 January 2021; revised manuscript received 15 February 2021; published online 25 February 2021
Citation 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
Keywords GMR effect, Granular state, Spin-dependent scattering, Permalloy, Superparamagnetism.
Annotation

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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