STRUCTURAL-PHASE TRANSFORMATIONS AND MAGNETIC PROPERTIES OF NANOSCALE Pt/Co-BASED THIN FILM COMPOSITIONS DEPOSITED ON FLEXIBLE POLYMER SUBSTRATES
DOI:
https://doi.org/10.20535/kpisn.2025.3.337638Keywords:
nanofilm composition; flexible polymer substrate; XRD, mass spectrometry; magnetization; coercivity.Abstract
Background. Ferromagnetic CoPt-based nanofilms continue to attract attention due to their potential applications in spintronics and nanoelectronics. They combine unique magnetic properties, high corrosion resistance, and compatibility with modern technologies for magnetic information storage devices and electromagnetic radiation detection. Co–Pt films are studied and applied as materials for sensors, tunnel junctions, magnetic disks, THz generators, and skyrmion carriers. Investigating the formation of their properties is a key task for the development of nanoelectronic technologies.
Objective. To determine the changes in phase composition, depth distribution of chemical elements, and magnetic properties of Pt/Co-based nanofilm compositions deposited on flexible polyimide substrates and subjected to subsequent heat treatment in high vacuum, with the addition of Au interlayers and the formation of varying numbers of interfacial boundaries.
Methodology. Pt/Co/PI, Pt/Au/Co/PI, and Pt/Co/Au/Pt/Co/PI nanofilms were deposited on flexible polyimide substrates by magnetron sputtering at room temperature. After deposition, the samples were annealed in vacuum at 550 °C for 30 minutes. Structural and phase changes were studied using X-ray diffraction (XRD) and mass spectrometry, while magnetic properties were examined using vibrating sample magnetometry (VSM) in an external magnetic field.
Research Results. It has been established that annealing nanoscale compositions at a temperature of 550 °C for 30 minutes leads to the formation of very small crystallites, most likely associated with the relaxation of stresses that arise in the film compositions during deposition. Mass spectrometry results indicate that annealing results in a uniform distribution of the intensity of secondary ion emission from the constituent metals of the film compositions, as well as from the complex CoPt ion, which points to the homogenization of the film compositions’ structure as a consequence of annealing. Magnetic property studies have shown that annealing enables the formation of a magnetically hard state in the film material, while its coercivity demonstrates a pronounced dependence on the initial structure of the composition.
Conclusions. It has been established that thermal treatment of nanoscale compositions Pt(10 nm)/Co(10 nm), Pt(10 nm)/Au(4 nm)/Co(10 nm), and Pt(5 nm)/Co(5 nm)/Au(4 nm)/Pt(5 nm)/Co(5 nm) deposited on polyimide substrates at 550 °C for 30 minutes allows the achievement of a magnetically hard state of the film material. At the same time, its coercivity exhibits a pronounced dependence on the structure of the initial composition namely, the presence of an additional Au layer and the number of interlayer interfaces.
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