Spin-polarized current through helimagnets and the conductance modulation due to the chirality mismatch is studied numerically. The one-dimensional spiral magnet structure is obtained by taking into account the Dzyaloshinskii-Moriya Interaction (DMI) and the Ferromagnetic (FM) interaction. Although the spiral magnetic structure consists of the y-z components of the magnetization, the conduction electron through the spiral magnet is polarized in the x direction and its sign depends on the chirality of the spiral structure. We also investigate the charge transport through the junction system consists of two helimagnets. Similar to the giant magnetoresistance in the uniform ferromagnet, the conductance is significantly reduced by attaching the helimagnets with different chiralities. Our proposed mechanism has a possibility of the chirality measuring method by using an electron transport and new type of magnetoresistance using a topological property.
Thermoelectric effects driven by magnetization dynamics under a temperature gradient are studied for ferromagnets with and without a skyrmion structure. We calculate charge currents in a four-terminal geometry using the adiabatic pumping formula with full account of magnetization dynamics based on the stochastic Landau–Lifshitz–Gilbert equation. The longitudinal current (Seebeck effect) is induced from the thermally driven spin waves via the spin-transfer and momentum-transfer processes, and these two processes contribute constructively (destructively) in ferromagnets having a negative (positive) s-d exchange interaction. The transverse currents (anomalous Nernst effect) arise in proportion to the number of skyrmions, whose mechanism is identified as the thermal topological Hall effect of magnons followed by the momentum-transfer drag process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.