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MA: Fachverband Magnetismus

MA 15: INNOMAG e.V. Prizes 2023 (Diplom-/Master and Ph.D. Thesis)

MA 15.2: Vortrag

Dienstag, 28. März 2023, 09:50–10:10, HSZ 401

Switching of Sublattice Magnetization in Quantum Antiferromagnets Described by Schwinger Bosons — •Katrin Bolsmann — Technische Universität Dortmund

Harvesting magnetic excitations in antiferromagnets for information processing is a promising and fast-growing field in the research of magnetism. One of the main foci is the readout and manipulation of the Néel vector of antiferromagnetic (AFM) materials. We study a theoretical approach to describe the non-equilibrium switching of a two-dimensional AFM magnetization on a square lattice. We recall the use of Schwinger bosons in equilibrium to describe the elementary excitations, of the isotropic and anisotropic AFM square lattice, in mean-field approximation. The Bose-Einstein condensation of Schwinger bosons describes the long-range magnetic order. Then, the Schwinger boson mean-field theory is applied to investigate the switching of the sublattice magnetization on the AFM square lattice via an external magnetic field. In the anisotropic system, there is an increase in energy after switching, which depends on the degree of anisotropy. Furthermore, we find a threshold field, below which switching is no longer possible, and investigate its dependence on the anisotropy. Even for low anisotropy, the threshold for the magnetic field turns out to be too large for standard technical applications. Finally, we discuss possible modifications of the protocol to enable switching of the sublattice magnetization with smaller fields.