This graduation thesis presents high-entropy alloys (HEA), which are alloys of at least five different elements of the periodic table, each present in comparable quantities. Over the past twenty years, they have been the subject of intensive research in the field of metallic materials. Due to their technological interest and potential use in various applications, they have also been studied for many years by the High-entropy alloys group at the F5 Solid State Physics Department of the Jožef Stefan Institute, investigating their electrical and magnetic properties. Most of the research is conducted on two measuring systems made by the USA manufacturer Quantum Design. The Physical Property Measurement System 9T (PPMS 9T) enables measurements of the physical properties of solids, while the Magnetic Property Measurement System 3 (MPMS 3) is designed to measure the magnetic properties of solids and liquids. As a part of my thesis, I participated in the research of a series of newly synthesized high-entropy alloys with the chemical formula (GaNi)xCoCrFe (x = 0.4–1.6), where the contents of gallium (Ga) and nickel (Ni) were jointly varied. Based on this research, the group has published a paper in the journal Materials & Design, to which I also refer in my thesis. I participated in the preparation of samples for measurements, in the measurement of magnetization, electrical resistance and magnetostriction (a change in length and shape in a magnetic field), and in the data processing and measurement results analysis. It was found that the alloys are ferromagnetic in nature and possess functional combination of magnetic softness and vanishing magnetostriction, which classifies them as energy-efficient super-silent materials suitable for electromagnetic applications with alternating current in the audio-frequency range.
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