Rare‐Earth Permanent Magnet SmCo₅ for Chiral Interfacial Spin‐Orbitronics

Abstract

Interfacially asymmetric magnetic multilayers made of heavy metal/ferromagnet have attracted considerable attention in the spintronics community for accommodating spin-orbit torques and meanwhile for hosting chiral spin textures. In these multilayers, 1 the accompanied interfacial Dzyaloshinskii-Moriya interaction (iDMI) permits the formation of Néel-type spin textures. While significant progresses have been made in Co, CoFeB, Co 2 FeAl, CoFeGd based multilayers, it would be intriguing to identify new magnetic multilayers which could enable spin-torque controllability and meanwhile host nanoscale skyrmions. In this report, we first synthesize thin films made of permanent magnet SmCo 5 with perpendicular magnetic anisotropy, in which the deterministic spin-orbit torque (SOT) switching, enabled by the spin Hall effect, in Pt/SmCo 5 /Ta trilayer is demonstrated. Further, we show the stabilization of roomtemperature skyrmions with diameters approximately 100 nm in [Pt/SmCo 5 /Ta] 15 , together with a skyrmionium-like spin texture in [Pt/SmCo 5 /Ir] 15 multilayers. Based on the material specific parameters, micromagnetic simulations are also carried out.Results of which confirm the presence of chiral spin textures in this new material family. Through interfacial engineering, our results thus demonstrate that rare earth permanent magnet could be a new platform for studying the interfacial chiral spintronics.

The 20-nm Skyrmion Generated at Room Temperature by Spin-Orbit Torques

“…The out-of-plane magnetic hysteresis loop ( M −H z) is measured by using VSM, as shown in Figure 1(b). The shape of the loop is similar to the typical multilayers that host Néel-type skyrmions [35,[41][42][43][44]. The saturation magnetization is estimated to be M s =¿ 1200 kAm -1 .…”

“…In particular, Néel-type skyrmions below 100 nm in diameter are observed at room temperature in Ir/Co/Pt multilayers [38,39], Co/Pd multilayer [40], Ir/Fe/Co/Pt multilayer [41,42], Pt/Co/IrMn multilayer [43] and Pt/SmCo/Ta multilayer [44]. Since the size of skyrmion directly determines the cell size of the skyrmion-based racetrack memory [45][46][47][48][49][50], the realization of the nanoscale skyrmions could substantially improve the storage density of these devices [25,[51][52][53][54][55][56].…”

A route to carbon-sp3 bridging spiro-molecules: synthetic methods and optoelectronic applications

“…[1][2][3][4] This includes rare earth permanent magnets, semiconductors, luminescent materials, ecological environments, energy, catalytic materials and technologies, and biomedical applications. [5][6][7][8][9][10][11][12][13][14][15] Among functional materials with different properties, organic functional materials have gained significant attention due to their abundant raw material sources, low cost, adjustable properties, light weight, flexibility, stretchability, tunable spectra, and the ability for largearea fabrication. 16,17 They have emerged as the most promising…”

A General Method for the Large‐Scale Preparation of Multifunctional Magnetic Sm‐Fe/Co Nanomaterials

“…[ 4 ] Some of these alloys show a strong uniaxial anisotropy like SmCo 5 , Sm 2 Co 17 , leading to a high magnetocrystalline anisotropy and large coercivity. [ 5–7 ] As an important medium to achieve the conversion between electrical and mechanical energy, they become especially key materials in artificial intelligence, unmanned aerial vehicle, intelligent robot and electromobile. [ 8–12 ] Some of them own the easy‐plane crystal structure such as Sm 2 Fe 17 , Ce 2 Fe 17 , making them show soft magnetic feature with high M s , high resonance frequency as well as permeability.…”

“…[4] Some of these alloys show a strong uniaxial anisotropy like SmCo 5 , Sm 2 Co 17 , leading to a high magnetocrystalline anisotropy and large coercivity. [5][6][7] As an important medium to achieve the conversion between electrical and mechanical energy, they become especially key materials in artificial intelligence, Herein, we report a new strategy that can synthesize stable RE-Fe/Co single crystal particles NPs without Ca-reduction process. The key process of this method is the preparation of REH x particles with size control using an evaporation-condensation process.…”