Two-terminal current-in-plane giant magnetoresistance devices driven by the spin–orbit torque

Prior to 2010, most research on the physics and chemistry of transition metal oxides was dominated by compounds of the 3d-transition elements such as Cr, Mn, Fe, Co, Ni, and Cu. These materials exhibited novel, important phenomena that include giant magnetoresistance in manganites, as well as high-temperature superconductivity in doped La2CuO4 and related cuprates. The discovery in 1994 of an exotic superconducting state in Sr2RuO4 shifted some interest toward ruthenates. Moreover, the realization in 2008 that a novel variant of the classic Mott metal-insulator transition was at play in Sr2IrO4 provided the impetus for a burgeoning group of studies of the influence of strong spin-orbit interactions in “heavy” (4d- and 5d-) transition-element oxides. This book reviews recent experimental and theoretical evidence that the physical and structural properties of 4d- and 5d-oxides are decisively influenced by strong spin-orbit interactions that compete or collaborate with comparable Coulomb, magnetic exchange, and crystalline electric field interactions. The combined effect leads to unusual ground states and magnetic frustration that are unique to this class of materials. Novel couplings between the orbital/lattice and spin degrees of freedom, which lead to unusual types of magnetic order and other exotic phenomena, challenge current theoretical models. Of particular interest are recent investigations of iridates and ruthenates focusing on strong spin-orbit interactions that couple the lattice and spin degrees of freedom.

Download Full-text

Giant Magnetoresistance Calculated from First Principles

MRS Proceedings ◽

10.1557/proc-313-59 ◽

1993 ◽

Vol 313 ◽

Cited By ~ 28

Author(s):

W. H. Butler ◽

James M. MacLaren ◽

X.-G. Zhang

Keyword(s):

Low Temperature ◽

First Principles ◽

Giant Magnetoresistance ◽

Coherent Potential Approximation ◽

Orbit Coupling ◽

Approximation Technique ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Potential Approximation ◽

Magnetoresis Tance

ABSTRACTThe Layer Korringa Kohn Rostoker-Coherent Potential Approximation technique was used to calculate the low temperature Giant Magnetoresistance from first principles for Co|Cu and permalloy|Cu superlattices. Our calculations predict large giant Magnetoresis-tance ratios for Co|Cu and extremely large ratios for permalloy|Cu for current perpendicular to the layers. Mechanisms such as spin-orbit coupling which mix spin channels are expected to greatly reduce the GMR effect for permalloy|Cu.

Download Full-text

Spin–Orbit Torques in Metallic Magnetic Multilayers: Challenges and New Opportunities

SPIN ◽

10.1142/s2010324717400136 ◽

2017 ◽

Vol 07 (03) ◽

pp. 1740013 ◽

Cited By ~ 9

Author(s):

Tao Wang ◽

John Q. Xiao ◽

Xin Fan

Keyword(s):

Giant Magnetoresistance ◽

Rapid Development ◽

Measurement Techniques ◽

Random Access ◽

Magnetic Multilayers ◽

Spin Transfer Torque ◽

Spin Torque ◽

Great Effort ◽

Spin Orbit ◽

Practical Applications

Two decades after the discovery of the giant magnetoresistance that revolutionizes the hard disk drive, the rapid development of spin torque-based magnetic random access memory has once again demonstrated the great potential of spintronics in practical applications. While the industrial application is mainly focusing on the implementation of current-induced spin transfer torque (STT) in magnetic tunnel junctions, a new type of spin torque emerges due to the spin–orbit interaction in magnetic multilayers. A great effort has been devoted by the scientific community to study the so-called spin–orbit torque (SOT), which is not only of interest to fundamental science, but also exhibits potential for the application of current-induced magnetization switching. In this paper, we will review recent development in the SOTs including the fundamental understanding, materials development and measurement techniques. We will also discuss the challenges of using the SOT in potential applications, particularly on the switching of perpendicularly magnetized films.

Download Full-text

Spin–orbit torque nano-oscillator with giant magnetoresistance readout

Communications Physics ◽

10.1038/s42005-020-00454-7 ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Jen-Ru Chen ◽

Andrew Smith ◽

Eric A. Montoya ◽

Jia G. Lu ◽

Ilya N. Krivorotov

Keyword(s):

Output Power ◽

Giant Magnetoresistance ◽

Ferromagnetic Layer ◽

Anisotropic Magnetoresistance ◽

Spin Orbit ◽

Major Drawback ◽

Practical Applications ◽

Reference Layer ◽

Signal Sources ◽

Nonmagnetic Metals

Abstract Spin-orbit torque nano-oscillators based on bilayers of ferromagnetic and nonmagnetic metals are ultra-compact current-controlled microwave signal sources. They are attractive for practical applications such as microwave assisted magnetic recording, neuromorphic computing, and chip-to-chip wireless communications. However, a major drawback of these devices is low output microwave power arising from the relatively small anisotropic magnetoresistance of the ferromagnetic layer. Here we experimentally show that the output power of a spin-orbit torque nano-oscillator can be significantly enhanced without compromising its structural simplicity. Addition of a ferromagnetic reference layer to the oscillator allows us to employ current-in-plane giant magnetoresistance to boost the output power of the device. This enhancement of the output power is a result of both large magnitude of giant magnetoresistance compared to that of anisotropic magnetoresistance and their different angular dependencies. Our results hold promise for practical applications of spin-orbit torque nano-oscillators.

Download Full-text

A two-terminal spin valve device controlled by spin–orbit torques with enhanced giant magnetoresistance

Applied Physics Letters ◽

10.1063/5.0055177 ◽

2021 ◽

Vol 119 (3) ◽

pp. 032406

Author(s):

Can Onur Avci ◽

Charles-Henri Lambert ◽

Giacomo Sala ◽

Pietro Gambardella

Keyword(s):

Giant Magnetoresistance ◽

Spin Valve ◽

Spin Orbit

Download Full-text

Semiconductor spintronics

Acta Physica Slovaca Reviews and Tutorials ◽

10.2478/v10155-010-0086-8 ◽

2007 ◽

Vol 57 (4-5) ◽

Cited By ~ 498

Author(s):

Jaroslav Fabian ◽

Alex Matos-Abiague ◽

Christian Ertler ◽

Peter Stano ◽

Igor Žutić

Keyword(s):

Giant Magnetoresistance ◽

Diluted Magnetic Semiconductors ◽

Semiconductor Device ◽

Orbit Coupling ◽

Full Potential ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Electronic Band ◽

Effective Spin ◽

Semiconductor Spintronics

Semiconductor spintronicsSpintronics refers commonly to phenomena in which the spin of electrons in a solid state environment plays the determining role. In a more narrow sense spintronics is an emerging research field of electronics: spintronics devices are based on a spin control of electronics, or on an electrical and optical control of spin or magnetism. While metal spintronics has already found its niche in the computer industry—giant magnetoresistance systems are used as hard disk read heads—semiconductor spintronics is yet to demonstrate its full potential. This review presents selected themes of semiconductor spintronics, introducing important concepts in spin transport, spin injection, Silsbee-Johnson spin-charge coupling, and spin-dependent tunneling, as well as spin relaxation and spin dynamics. The most fundamental spin-dependent interaction in nonmagnetic semiconductors is spin-orbit coupling. Depending on the crystal symmetries of the material, as well as on the structural properties of semiconductor based heterostructures, the spin-orbit coupling takes on different functional forms, giving a nice playground of effective spin-orbit Hamiltonians. The effective Hamiltonians for the most relevant classes of materials and heterostructures are derived here from realistic electronic band structure descriptions. Most semiconductor device systems are still theoretical concepts, waiting for experimental demonstrations. A review of selected proposed, and a few demonstrated devices is presented, with detailed description of two important classes: magnetic resonant tunnel structures and bipolar magnetic diodes and transistors. In view of the importance of ferromagnetic semiconductor materials, a brief discussion of diluted magnetic semiconductors is included. In most cases the presentation is of tutorial style, introducing the essential theoretical formalism at an accessible level, with case-study-like illustrations of actual experimental results, as well as with brief reviews of relevant recent achievements in the field.

Download Full-text

Origin of the Dzyaloshinskii-Moriya Interactions in the Intermetallic RMn2Si2 ( R= La, Ce, Yb and Y) Materials: A DFT Study

10.21203/rs.3.rs-289033/v1 ◽

2021 ◽

Author(s):

Widad Bazine ◽

Najim TAHIRI ◽

Omar Elbounagui ◽

Hamid Ez-Zahraouy

Keyword(s):

Ab Initio Calculations ◽

Ab Initio ◽

Density Of States ◽

First Principles ◽

Giant Magnetoresistance ◽

Dft Study ◽

Spin Orbit ◽

First Principles Calculations ◽

Strong Hybridization ◽

Large Spin

Abstract The Dzyaloshinskii-Moriya interactions (DM) are investigated using first-principles calculations by means of the WIENNCM code, an implementation of the FP-LAPW method. The intermetallic RMn2Si2 (R = La, Ce, Yb, and Y) materials exhibit a large spin-orbit effect after the density of states; they found a strong hybridization between Mn-Si and Mn-R atoms. Also, show a large noncollinear magnetic configuration depending on the R atoms. By using ab-initio calculations, the RKKY effect is observed in the RMn2Si2 materials, which shows explicitly the existence of the giant magnetoresistance (GMR) in these materials. Explicitly, the mechanisms responsible for the magnetoelectric coupling are due to relatively the effect of the presence of the Dzyaloshinskii-Moriya term.

Download Full-text