1158 ISSN 1063-7834, Physics of the Solid State, 2018, Vol. 60, No. 6, pp. 1158–1162. © Pleiades Publishing, Ltd., 2018. Original Russian Text © I.A. Baraban, A.V. Emelyanov, P.N. Medvedskaya, V.V. Rodionova, 2018, published in Fizika Tverdogo Tela, 2018, Vol. 60, No. 6, pp. 1147–1151. Low Temperature Magnetic Properties of Amorphous Ferromagnetic Fe–Si–B Glass-Coated and Glass Removed Microwire 1 I. A. Baraban a , A. V. Emelyanov b , P. N. Medvedskaya a , and V. V. Rodionova a, * a Immanuel Kant Baltic Federal University, Kaliningrad, 234041 Russia b National Research Center “Kurchatov Institute,” Moscow, 123182 Russia *e-mail: rodionova@lnmm.ru Received December 25, 2017 Abstract—This work presents results of investigations of low temperature magnetic properties of microwires, fabricated by the Ulitovsky–Taylor method from Fe–Si–B alloy. Influence of the glass coating presence on the magnetostatic properties was shown at room temperature and at 2 K. Conclusions about the peculiarities of temperature dependence of the magnetic moment, measured in low and high magnetic fields (10 Oe– 5 kOe) in the temperature range from 2 to 300 K for a sample with partially reduced fabricated process- induced stress by removing the glass, were made. DOI: 10.1134/S1063783418060070 1. INTRODUCTION Amorphous ferromagnetic glass-coated microw- ires with Fe-based metallic nucleus exhibit properties of magnetic bistability in a wide range of their dimen- sions—both the transverse [1–3] and longitudinal [4– 6], as well as in a wide temperature range [7–9]. Mag- netic bistability opens a lot of prospects for the practi- cal use for microwires, for example, as a sense element of sensors of various physical quantities (stress, tem- perature, magnetic field, and others) [10, 11], as a functional element of the coding and reading systems [12, 13]. The nature of the magnetic bistability of glass- coated amorphous ferromagnetic microwires is in the micromagnetic structure—Landau–Lifshitz [14], formed during the process of microwires manufactur- ing by the Ulitovsky–Taylor method. In this case, a large volume of the metallic nucleus is occupied by an axially magnetized core, and a small volume on the periphery has a domain structure with a radially directed axis of easy magnetization [15]. The volume of closure domains, arising in the microwire due to the system’s aiming to minimize the magnetostatic energy, depends, first of all, on the demagnetizing field of microwire and essentially increases with an increase of the form factor of the sample (a decrease in the length or increase in diameter at a fixed second parameter) [6]. Magnetoelastic energy, K me ~ 3/2λ S σ, plays a cru- cial role in the formation of micromagnetic structure and, consequently, of magnetic properties of the metallic nucleus of a glass-coated microwire (because transverse dimensions of the sample are much smaller than its longitudinal dimensions and the material of the metallic nucleus is amorphous, the magnetostatic energy and magnetocrystalline energy, respectively, can be neglected) [16]. Therefore, the direction of the mechanical stress σ and the sign of the magnetostric- tion coefficient λ S determine the direction of the easy magnetization axis. Mechanical stresses σ are induced in the metallic nucleus of the microwire during the Ulitovsky–Taylor technique, because of the fast quenching process, difference in the thermal expan- sion coefficients of the metal and glass, and of the applied mechanical tensile stress (drawing). Radial distribution of the components σ ii of the mechanical stress tensor of the metallic nucleus is formed in such a way that the tensile stresses are dominant in a larger volume of the metallic nucleus of the wire (up to 0.95d/D, where d is the diameter of the metallic nucleus of the microwire, and D is the total diameter of the microwire in the glass shell) [16, 17]. Therefore, to form a Landau–Lifshitz-wise structure where an axially magnetized core occupies a larger volume of the metallic nucleus, it is sufficient to select for fabri- cation a high magnetostrictive material with a positive magnetostriction coefficient λ S , for example Fe–Si– B. In this case, the metallic nucleus of the microwire can be considered as a single domain (at sufficient 1 The article was translated by the authors. MAGNETISM