Colloids of HEA nanoparticles in an imidazolium-based ionic liquid prepared by magnetron sputtering: Structural and magnetic properties

• Published in: Journal of alloys and compounds 2022-03, Vol.896, p.163089, Article 163089
• Main Authors: Dvurečenskij, A., Cigáň, A., Lobotka, P., Radnóczi, G., Škrátek, M., Benyó, J., Kováčová, E., Majerová, M., Maňka, J.
• Format: Article
• Language: English
• Subjects: Cluster/Spin glass; Colloids; High entropy alloys; High-entropy alloy nanoparticles; Ionic liquid; Ionic liquids; Ions; Magnetic measurement; Magnetic properties; Magnetism; Magnetron sputtering; Molar magnetic susceptibility; Nanoalloys; Nanoparticles; Single crystals; Size distribution; SQUID magnetometry; Superconducting quantum interference devices; Vapor pressure
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.163089

•Colloids of HEA nanoparticles in IL were prepared by the DC magnetron sputtering.•HEA nanoparticles colloids were studied by HRTEM microscopy and SQUID magnetometry.•For pure IL at the high applied H the long-range magnetic moment ordering occurs.•Under 70 K, some strong changes, jumps, are present in the ZFC characteristics.•Magnetic measurements imply interactions between the IL and the HEA nanoparticles. Colloids consisting of the CoCrCuFeNi high-entropy alloy nanoparticles in ionic liquid with the 1-butyl-3-methylimidazolium ([BMIM]+) cation and the tetrafluorborate ([BF4]-) anion were obtained by the DC magnetron sputtering of high-entropy alloy target in vacuum, onto the surface of [BMIM.BF4] ionic liquid. The method of the nanoparticle colloid preparation is based on negligibly small vapour pressure of the ionic liquid, which allows its application in vacuum. The high-entropy alloy nanoparticle colloids were studied by HRTEM microscopy and SQUID magnetometry. Results of the structural and magnetic analyses show that the colloids contain ultra-small single-crystalline nanoparticles of an uneven shape and typical size of (2−3) nm. The nanoparticles have relatively narrow size distribution which is typical for this preparation method. The high-entropy alloy nanocolloids show complex magnetic properties that are a function of temperature, applied magnetic field and mass content of the nanoparticles in the colloids. The obtained results imply significant magnetic interactions between the ionic liquid and the high-entropy alloy nanoparticles.