Interaction of Magnetization Centers of Different Signs as the Cause of the Nonmonotonic Field Dependence of the Domain Wall Velocity in Synthetic Pt/Co/Ir/Co/Pt Ferrimagnets

• Published in: Journal of experimental and theoretical physics 2019-12, Vol.129 (6), p.998-1004
• Main Authors: Bezverkhnii, A. I., Talantsev, A. D., Mangin, S., Morgunov, R. B.
• Format: Article
• Language: English
• Subjects: Anisotropy; Classical and Quantum Gravitation; Cobalt; Dependence; Disorder; Domain walls; Elementary Particles; Ferrimagnetism; Ferrimagnets; Ferromagnetism; Iridium; Magnetic anisotropy; Magnetic moments; Magnetism; Magnetization; Nucleation; Order; Particle and Nuclear Physics; Phase Transition in Condensed System; Physics; Physics and Astronomy; Platinum; Quantum Field Theory; Relativity Theory; Solid State Physics; Thickness; Thin films
• ISSN: 1063-7761; 1090-6509
• DOI: 10.1134/S1063776119120021

The purpose of the work is to find the dependence of growth rate of magnetization centers of various types on their surrounding by other nucleation centers in a synthetic Pt/Co/Ir/Co/Pt ferrimagnet with perpendicular magnetic anisotropy. The following four types of nucleation centers exist in a sample with two ferromagnetic layers of different thicknesses: P + centers correspond to the regions where the magnetizations of the thick and thin Co layers are directed along an applied field (↑↑); P – centers are the regions where the magnetizations of the layers are opposite to an applied field (↓↓); and AP + and AP – centers correspond to the regions where the magnetizations of the thick and thin Co layers are opposite to each other and the total magnetic moment is along (↑↓) or opposite to (↓↑) an applied field, respectively. P – nucleation centers are found to be surrounded by AP + regions in any field and exhibit a monotonic field dependence of their boundary. The field dependence of the growth rate of AP – nucleation centers is nonmonotonic since, as the field increases, they are surrounded by AP + nucleation centers, AP + and P – regions, and only P – nucleation centers in strong fields.