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Toward low-energy-consumption spintronic devices, magnetic multilayers that host chiral spin textures, as well as efficient spin-torques, are highly promising. As compared with resistive materials, superconducting materials are optimal for constructing dissipationless electronic devices, in which the electricity is conducted without producing Joule heating. In this regard, magnetic multilayers containing superconductors are well suited for building ultra-low power spintronic devices. Following this motivation, we study the possible existence of chiral spin textures in the two-dimensional (2D) high temperature superconductor/ferrimagnet heterostructures of stacking order Bi2Sr2CaCu2O8+δ/Fe1−xTbx and stacking order Bi2Sr2CaCu2O8+δ/Co1−xTbx. Through x-ray photon-emission electron microscopy, we observe bubble-like spin textures in a wide temperature range. Based on the first-principles calculations, the important role of spin–orbit interaction from the BiO termination layer is discussed, which induces a very large interfacial Dzyaloshinskii–Moriya interaction and results in the possible existence of chiral spin textures on top of superconductors. Our work suggests that the layered high-temperature superconductor could be incorporated for stabilizing chiral spin textures and for building dissipationless spin-orbitronic devices. [ABSTRACT FROM AUTHOR]

Spin valve effect driven by current-induced spin–orbit torques can help to realize electrically controllable and miniaturized two terminal spintronic devices. Here, we show that in a perpendicularly magnetized Fe 1 − x 1 Tb x 1 /Pt/ Fe 1 − x 2 Tb x 2 spin-valve multilayer, spin currents from dual surfaces of the inserted Pt layer can be used to generate spin torques that can separately switch the adjacent ferrimagnetic Fe1−xTbx layers. In a two-terminal device, we further show that the accompanied parallel and anti-parallel magnetization configurations between the two Fe1−xTbx layers can lead to the observation of the current-in-plane giant magnetoresistance (CIP-GMR). Our results demonstrate that the current-induced spin–orbit torques can be implemented into two-terminal spin-torque devices, which can be electrically read out by the CIP-GMR. The present study could be important for designing miniaturized spintronic devices. [ABSTRACT FROM AUTHOR]

The spin–orbit torques (SOTs) induced by spin currents in the heavy metal/ferromagnet (HM/FM) bilayer are of great importance for enabling nonvolatile, low power consumption spintronics. In the standard HM/FM bilayers, only the spin current at the interface is employed for implementing SOTs. Another part of the spin current with the opposite spin polarization, which is generated at the opposite side of the HM layer, is supposably not put into action. Here, we will show the experimental feasibility of utilizing spin currents from the dual surfaces of the HM Pt layer. In particular, through synthesizing perpendicularly magnetized Fe 1 − x 1 Tb x 1 /Pt/ Fe 1 − x 2 Tb x 2 trilayers, we demonstrate that spin currents at the dual surfaces of the Pt layer can be simultaneously used to deterministically switch the perpendicular magnetization vectors of the neighboring Fe1-xTbx layers, through the current-induced SOTs. Based on the second harmonic measurement, we further quantify the enhanced efficiency of the current-induced SOTs. A three-dimensional spintronic device that can host an exponentially increased magnetization states is also demonstrated. Our results could be important for enabling more energy efficient spin-orbitronics that could be used in multistate memory and spin logic devices. [ABSTRACT FROM AUTHOR]

Van der Waals (vdW) ferromagnetic materials have attracted considerable attention in the nanomaterial community, which could provide a unique platform to study magnetism at the nanoscale. Along this direction, many interesting results have been reported, including the electric field control of magnetism and topological spin textures. In this report, we present a rapid and spatially resolved imaging method to study the dimensionality-dependent magnetic properties of Fe3GeTe2 (FGT) nanoflakes. Our method is named as polar magneto-optical Kerr imaging microscopy magnetometry (p-MIMM), which is made possible by analyzing the intensity evolution of wide-field polar magneto-optical Kerr effect (MOKE) images that were collected by varying magnetic fields, thicknesses, and temperatures. In particular, spatially resolved MOKE hysteresis loops can be acquired in the FGT nanoflakes with a submicrometer resolution. By analyzing the evolution of the relative (saturated) MOKE intensity as a function of temperature, we further study the critical exponent and universality class and its dependence on the FGT nanoflake thickness. Combining the polar MOKE images with the calculated MOKE hysteresis loops, a detailed magnetic phase diagram summarizing an evolution of the stripe domain, single domain, and paramagnetic state is further validated. Our results suggest that the wide-field p-MIMM can be conveniently used for rapidly examining the magnetic properties of versatile vdW magnetic materials. [ABSTRACT FROM AUTHOR]