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Öğe A review of soft magnetic properties of mechanically alloyed amorphous and nanocrystalline powders(Springernature, 2023) Yakın, Alican; Şimşek, Tuncay; Avar, Barış; Şimşek, Telem; Chattopadhyay, Arun K.The development of soft magnetic materials is fundamentally important for improving operational efficiencies of the ever-growing field of power electronics, electrical motors, and generators. It requires to meet the challenges of constantly changing fields of modern areas of applications starting from spaceships to day-to-day electronics. Many new materials with soft magnetic properties, viz. ferrous alloys, soft ferrites, amorphous and nanocrystalline magnetic alloys, have been continuously evolving since the inception of electromagnetic induction. The main drive for the continuous improvements of soft magnetic materials is primarily to enhance energy efficiency, to reduce size and weight, and to boost the power of high-frequency power electronics and electrical machines of high rotational speed. Despite some predicaments, the amorphous and nanocrystalline soft magnetic materials have become a field of major research interest since their invention four decades ago. It has been observed that the amorphous and nanocrystalline alloys exhibit better magnetic properties than the conventional soft magnetic alloys. This group of materials is produced adapting various production techniques. In this review, amorphous, nanocrystalline, and high entropy alloys (HEA) are discussed as soft magnetic materials and their electromagnetic properties are assessed. However, this review will particularly focus on the mechanically alloyed amorphous, nanocrystalline, and HEA soft magnetic materials. The soft magnetic alloys of interest for this review are grouped on the basis of Fe, Co, Ni, and FeCoNi. Furthermore, the effect of MA parameters and subsequent annealing processes on the magnetic properties is also assessed. This review brings forth a great promise in the field of soft-core magnets for high-end applications.Öğe A single step synthesis by mechanical alloying and characterization of nanostructured Fe2B of high magnetic moment(Elsevier Sci Ltd, 2021) Şimşek, Telem; Avar, Barış; Şimşek, Tuncay; Yıldız, Büşra; Chattopadhyay, Arun K.; Özcan, ŞadanThis paper delineates a single-step production method of nanostructured diiron boride (Fe2B) and its structural, magnetic and magnetothermal properties. Structurally Fe2B resembles the tetragonal copper aluminide, CuAl2. The samples of nanostructured Fe2B were synthesized by milling Fe and B powders without any pre-treatment. Single phase Fe2B nanoparticles were successfully produced with the crystallite sizes of 68 and 46 nm after milling the powders for 10 h and 20 h, respectively. The saturation magnetization of the samples was found to decrease with increased milling time indicating that the surface spin disorder plays a crucial role in the magnetic properties. The highest saturation magnetization (Ms) of 141 emu/g with low coercivity (Hc) of 48 Oe was obtained for the 10 h milled sample of Fe2B, whereas the 20 h milled sample exhibited Ms and Hc as 129 emu/g and 149 Oe. This paper also presents a detailed information on the total and atom projected densities of state functions as well as the magnetic moment contribution of the individual atoms of Fe and B in Fe2B explaining the strong room temperature ferromagnetic properties contributed by the large number of unpaired 3 d electrons in Fe. The magnetothermal properties of the as-made Fe2B nanocrystals of high magnetic moment were investigated by measuring the rise in temperature as a function of time in the presence of AC magnetic fields. The magnetic Fe2B nanocrystals show significant thermal response with the high specific absorption rate of 172 W/g, demonstrating the advantages of using Fe2B nanocrystals for the application in magnetic fluid therapy for hyperthermia.Öğe Correction: Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy (Journal of Materials Research, (2022), 37, 14, (2271-2281), 10.1557/s43578-022-00625-y)(Springer Nature, 2022) Özkul, İskender; Karaduman, Oktay; Şimşek, Telem; Şimşek, Tuncay; Canbay, Canan Aksu; Ibrahim, Pshdar Ahmed; Arpa, İpek AkThis article was updated to correct İpek A. K. Arpa’s name. © The Author(s), under exclusive licence to The MaterialsResearch Society 2022.
