Search for: All records

In easy-plane magnets, the spin superfluid phase was predicted to facilitate coherent spin transport. So far, experimental evidence remains elusive. In this Letter, we propose an indirect way to sense this effect via the spin superfluid quantum interference device (spin SQUID), inspired by its superconducting counterpart (rf SQUID). The spin SQUID is constructed as a quasi-one-dimensional (1D) magnetic ring with a single Josephson weak link, functioning as an isolated device with a microwave response. The spin current is controlled by an in-plane electric field through Dzyaloshinskii-Moriya interaction. This interaction can be interpreted as a gauge field that couples to the spin supercurrent through the Aharonov-Casher effect. By investigating the static and dynamic properties of the device, we show that the spin current and the harmonic frequencies of the spin superfluid are periodic with respect to the accumulated Aharonov-Casher phase and are, therefore, sensitive to the radial electric flux through the ring in units of an electric flux quantum, suggesting a potential electric-field sensing functionality. For readout, we propose to apply spectroscopic analysis to detect the frequency shift of the harmonic modes induced by this magnonic Stark effect. 

In superconductors that lack inversion symmetry, a supercurrent flow can lead to nondissipative magne- toelectric effects. We offer a straightforward formalism to obtain a supercurrent-induced magnetization in superconductors with broken inversion symmetry, which may have orbital, layer, sublattice, or valley degrees of freedom—multiband noncentrosymmetric superconductors. The nondissipative magnetoelectric effect may find applications in fabricating quantum computation platforms or efficient superconducting spintronic devices. We explore how the current-induced magnetization can be employed to create and manipulate Majorana zero modes in a simple hybrid structure. 

We consider magnetic Weyl metals as a platform to achieve current control of magnetization textures with transport currents utilizing their underlying band geometry. We show that the transport current in a Weyl semimetal produces an axial magnetization due to orbital magnetic moments of the Weyl electrons. The associated axial magnetization can generate a torque acting on the localized magnetic moments. For the case of a magnetic vortex in a nanodisk of Weyl materials, this current-induced torque can be used to reverse its circulation and polarity. We discuss the axial magnetization torques in Weyl metals on general symmetry grounds and compare their strength to current-induced torques in more conventional materials. 

Abstract Antiferromagnets (AFMs) have the natural advantages of terahertz spin dynamics and negligible stray fields, thus appealing for use in domain-wall applications. However, their insensitive magneto-electric responses make controlling them in domain-wall devices challenging. Recent research on noncollinear chiral AFMs Mn₃X (X = Sn, Ge) enabled us to detect and manipulate their magnetic octupole domain states. Here, we demonstrate a current-driven fast magnetic octupole domain-wall (MODW) motion in Mn₃X. The magneto-optical Kerr observation reveals the Néel-like MODW of Mn₃Ge can be accelerated up to 750 m s^-1with a current density of only 7.56 × 10¹⁰A m^-2without external magnetic fields. The MODWs show extremely high mobility with a small critical current density. We theoretically extend the spin-torque phenomenology for domain-wall dynamics from collinear to noncollinear magnetic systems. Our study opens a new route for antiferromagnetic domain-wall-based applications.