Citation: Stoklosa, Z.; Kwapuli´ nski, P.; Karolus, M. Magnetization Processes in Metallic Glass Based on Iron of FeSiB Type. Materials 2022, 15, 9015. https://doi.org/10.3390/ ma15249015 Academic Editor: Antoni Planes Received: 25 November 2022 Accepted: 14 December 2022 Published: 16 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). materials Article Magnetization Processes in Metallic Glass Based on Iron of FeSiB Type Zbigniew Stoklosa * , Piotr Kwapuli ´ nski and Malgorzata Karolus Institute of Materials Science, University of Silesia, 75-go Pulku Piechoty 1a, 41-500 Chorzów, Poland * Correspondence: zbigniew.stoklosa@us.edu.pl Abstract: In the present paper, the magnetization processes in amorphous alloys based on iron are discussed in detail. Our main goal was to measure the stabilization energy connected with the presence of microvoids (frozen during rapid cooling from the liquid phase) and to determine the interaction energy of relaxators with spontaneous magnetization vector (the so-called w N Neel) for amorphous Fe 78 Si 13 B 9 alloys. A structural analysis of the alloys using X-ray measurements at the subsequent stages of crystallization was also performed. Keywords: amorphous alloys; soft magnetic materials; magnetization processes; XRD analysis 1. Introduction Iron-based amorphous alloys, due to their unique properties, are an interesting group of soft magnetic materials [1–5]. The magnetic parameters of these alloys are much better in comparison to silicon steels, and can be significantly improved by applying a controlled thermal treatment. [6–8]. Improvement of soft magnetic properties can be obtained by nanocrystallization or by formation of the so-called relaxed amorphous phase [9–15]. Magnetization processes of amorphous alloys based on iron are complex processes and depend on many elements. The thermodynamic free energy of crystalline ferromagnetic samples, according to Morrish [16], is the sum of following components (with the accuracy of the additive constant F 0 ): F = F 0 + F H + F D + F K + F σ + F e + F S (1) where F H is the energy connected with the magnetization of the sample in an applied magnetic field H, F D is the energy connected with the magnetization of sample in their own magnetic field, F K is the magnetocrystalline anisotropy energy, F σ is the magnetoelastic energy, F e is the exchange energy, and F S is the stabilisation energy. In amorphous soft magnetic materials, magnetoelastic energy and stabilisation en- ergy, connected with the presence of relaxators, play a dominant role. The relaxators are atoms paired in the presence of free volumes (so-called microvoids) [17,18], frozen during rapid cooling from the liquid phase. In the case of nanocrystalline materials, the magnetocrystalline anisotropy energy dominates. The main goal of the present work is to determine the stabilization energy connected with the presence of microvoids and the interaction energy of relaxators with spontaneous magnetization vectors (the so-called w N Neel) for amorphous Fe 78 Si 13 B 9 alloys. Magnetic delay, also called magnetic viscosity, originally observed in crystalline mate- rials, is related to the migration of atoms of impurities or defects in the crystal lattice. This phenomenon also occurs in structurally disordered materials—in amorphous alloys. In the case of these materials, the delay phenomenon is caused by the directional ordering of atom pairs near the so-called free volumes [17,18]. Several phenomena caused by magnetic viscosity are known, including: • Magnetic susceptibility disaccomodation; Materials 2022, 15, 9015. https://doi.org/10.3390/ma15249015 https://www.mdpi.com/journal/materials