Search results for "Spintronics"

Epitaxial Mn2Au thin films for antiferromagnetic spintronics

2015

Mn2Au is one of the few candidate materials for antiferromagnetic spintronics requiring ordered metals with a high Neel-temperature and strong spin–orbit coupling. We report the preparation of epitaxial Mn2Au thin films by rf-sputtering. Structural characterization by x-ray and electron diffraction demonstrates a high degree of atomic order and the temperature dependence of the resistivity is typical for a good metal. The magnetic properties of the samples are studied by the investigation of Mn2Au/Fe bilayers. Exchange bias effects are observed, which present strong evidence for antiferromagnetic order in the Mn2Au thin films. Small domains of 500 nm are visualized in the exchange coupled F…

Thickness dependence of anomalous Hall conductivity in L10-FePt thin film

2019

L10 ordered alloys are ideal models for studying the anomalous Hall effect (AHE), which can be used to distinguish the origin from intrinsic (from band structure) or from extrinsic effects (from impurity scatterings). In the bulk limit of L10 ordered FePt films, the AHE is considered to be dominated by the intrinsic contribution, which mainly comes from the strong spin-orbit interaction (SOI) of Pt atoms and exchange-splitting of Fe atoms. The study of anomalous Hall conductivity (AHC) of L10-FePt thin films is of particular interest for its application in spintronic devices. In order to reduce the effects of defects such as grain boundaries, we chose SrTiO3 as the substrate which has a ver…

Publisher's Note: “Low intrinsic carrier density LSMO/Alq3/AlOx/Co organic spintronic devices” [Appl. Phys. Lett. 112, 142401 (2018)]

2018

Spin polarized tunneling at room temperature in a Heusler compound-a non-oxide material with a large negative magnetoresistance effect in low magneti…

2003

Summary form only given. Materials which display large changes in resistivity in response to an applied magnetic field (magnetoresistance) are currently of great interest due to their potential for applications in magnetic sensors, magnetic random access memories, and spintronics-a new kind of electronics based on spin instead of charge. Although ferromagnetic manganites show colossal magnetoresistance (CMR) effects around their Curie temperature, the low field and nearly temperature independent magnetoresistance properties important for spintronics are found only at low temperatures. Guided by striking features in the electronic structure of several magnetic compounds, we prepared the Heus…

Rational design of new materials for spintronics: Co2FeZ (Z=Al, Ga, Si, Ge)

2008

Spintronic is a multidisciplinary field and a new research area. New materials must be found for satisfying the different types of demands. The search for stable half-metallic ferromagnets and ferromagnetic semiconductors with Curie temperatures higher than room temperature is still a challenge for solid state scientists. A general understanding of how structures are related to properties is a necessary prerequisite for material design. Computational simulations are an important tool for a rational design of new materials. The new developments in this new field are reported from the point of view of material scientists. The development of magnetic Heusler compounds specifically designed as …

Quaternary half-metallic Heusler ferromagnets for spintronics applications

2011

This work reports on three quaternary Heusler compounds NiFeMnGa, NiCoMnGa, and CuCoMnGa. In contrast to their ternary relatives, quaternary Heusler compounds are still rarely investigated. A very large pool of interesting materials lies thus idle waiting for exploration. The difficulty consists in choosing prospective compositions, and trial and error is elaborate and expensive. We have identified several candidates employing ab initioelectronic-structure calculations. The compounds were synthesized, and the structural and magnetic properties were investigated experimentally. CuCoMnGa is a quaternary Heusler compound; NiFeMnGa and NiCoMnGa are unreported half-metallic ferromagnetic materia…

Spintronics and Nanomemory Systems

2017

The chapter presents and explains the possibilities of CNT forest growth on Fe–Pt nanoparticles for the magnetic nanomemory. The magnetoresistance phenomena – giant magnetoresistance and tunnelling magnetoresistance (GMR and TMR) – for nanomemory devices are based on CNTs of various morphologies (i.e. various chiralities, diameters). It includes metal- and semiconductor-like CNTs which can be considered as alternative variants for electromagnetic nanosensoring and magnetic nanomemory. The chapter also presents simulations of Fe–Pt magnetically disordered nanodrops, as well as spin transport models.

Surface resonance of thin films of the Heusler half-metal Co2MnSi probed by soft x-ray angular resolved photoemission spectroscopy

2019

Heusler compounds are promising materials for spintronics with adjustable electronic properties including 100% spin polarization at the Fermi energy. We investigate the electronic states of ${\mathrm{AlO}}_{x}$ capped epitaxial thin films of the ferromagnetic half-metal ${\mathrm{Co}}_{2}\mathrm{MnSi}$ ex situ by soft x-ray angular resolved photoemission spectroscopy (SX-ARPES). Good agreement between the experimental SX-ARPES results and photoemission calculations including surface effects was obtained. In particular, we observed in line with our calculations a large photoemission intensity at the center of the Brillouin zone, which does not originate from bulk states, but from a surface r…

Electrical switching of perpendicular magnetization in a single ferromagnetic layer

2020

We report on the efficient spin-orbit torque (SOT) switching in a single ferromagnetic layer induced by a new type of inversion asymmetry, the composition gradient. The SOT of 6- to 60-nm epitaxial FePt thin films with a $L{1}_{0}$ phase is investigated. The magnetization of the FePt single layer can be reversibly switched by applying electrical current with a moderate current density. Different from previously reported SOTs which either decreases with or does not change with the film thickness, the SOT in FePt increases with the film thickness. We found the SOT in FePt can be attributed to the composition gradient along the film normal direction. A linear correlation between the SOT and th…

Electric-Field Control of Spin-Orbit Torques in Perpendicularly Magnetized W/CoFeB/MgO Films

2020

Controlling magnetism by electric fields offers a highly attractive perspective for designing future generations of energy-efficient information technologies. Here, we demonstrate that the magnitude of current-induced spin-orbit torques in thin perpendicularly magnetized CoFeB films can be tuned and even increased by electric-field generated piezoelectric strain. Using theoretical calculations, we uncover that the subtle interplay of spin-orbit coupling, crystal symmetry, and orbital polarization is at the core of the observed strain dependence of spin-orbit torques. Our results open a path to integrating two energy efficient spin manipulation approaches, the electric-field-induced strain a…