Torque causes an object to spin around a fixed axis. For integrated solidstate memory applications, it is important to understand the magnetic and electrical characteristics of these magnetic tunnel junctions as they. Evaluation of forces and torques generated by toroidal. The manipulation and detection of magnetization in ferromagnetic layers using spintransfer torque stt have received considerable attention. Transmission torque analysis of a novel magnetic planetary. We present measurements of currentinduced spinorbit torques generated by nbse2, a fully metallic transitionmetal dichalcogenide material, made using the spintorque ferromagnetic resonance stfmr technique with nbse2permalloy bilayers. We found that electric current parallel to \2\bar1\bar10\ and 0001 in the hexagonal 4index notation induces a uniform. We can also see that the knowledge of forces and moments caused by this particular. Currentinduced spinorbit torques mediate the transfer of angular momentum. Size dependence of spintorque induced magnetic switching in. Currentinduced torques in magnetic materials nature materials.
Lomonova department of electrical engineering, group of electromechanics and power electronics, eindhoven university of technology, 5600 mb, the netherlands. Currentinduced spin torque resonance of a magnetic insulator. Enhancing currentinduced torques by abutting additional. Transmission torque analysis of a novel magnetic planetary gear employing 3d fem noboru niguchi and katsuhiro hirata department of adaptive machine systems, graduate school of engineering, osaka university, suita, osaka 5650871, japan this paper describes the transmission torque characteristics of a novel magnetic planetary gear. Current induced ferromagnetic resonance cifmr is an effective method to characterize ferromagnetic samples at micrometrescale and quantify the current induced magnetic torques in.
This thesis uses ferromagnetic resonance to explore the current induced torques cits in two different systems, namely yigheavy metal bilayers and bulk nimnsb, at room temperature. Enhancement of spin orbit torques in a tbco alloy magnetic. Deterministic spinorbit torque switching by a lightmetal insertion. Currentinduced switching of perpendicularly magnetized. Thickness dependence study of currentdriven ferromagnetic. Currentinduced torque driven ferromagnetic resonance in. Currentinduced torques in ferromagnets at room temperature. Bergers paper focused on the emission of spin waves as the source of magnetic excitations, while slonczewski invoked conservation of spin. Tunable electromagnetically induced transparency in. Buhrman1 1cornell university, ithaca, new york 14853, usa 2kavli institute at cornell, ithaca, new york, 14853 received 24 april 2012. Methods to manipulate the magnetization of ferromagnets by means of local electric fields or currentinduced spin transfer torque allow the design of integrated spintronic devices with reduced dimensions and energy consumption compared with conventional magnetic field actuation. From the dw motion study, a monotonous decay of the effective dmi strength with increasing co thickness is observed, in agreement with a dmi originating. Relativistic torques induced by currents in magnetic materials. Transmitted torque analysis of a magnetic gear mechanism with.
The dependence of resistance and currentdriven torque on relative angle between. Due to their strong spinorbit coupling and wellunderstood bandstructure, these materials are wellsuited to this investigation. Examples of objects that have magnetic moments include. Currentinduced torques in magnetic materials arne brataas1, andrew d. Pdf spinorbit coupling in inversionasymmetric magnetic crystals and structures has emerged as a. Numerical and analytical studies of current induced. Currentdriven ferromagnetic resonance, mechanical torques and rotary motion in magnetic nanostructures alexey a. First, we applied an outofplane magnetic field that is much higher than the coercivity to saturate the wire magnetization. The system has already been partially described in 6, but for the convenience of the reader, its working principle is summarized in the following. Currentinduced torques with dresselhaus symmetry due to. Magnetization measurements under direct electric current were performed in a toroidal magnetic ordered state of uni 4 b to test a recent theoretical prediction of currentinduced magnetization in a metallic system lacking localinversion symmetry.
In this respect, spinorbit torque sot, which originates from the spinorbit interaction, has been widely investigated due to its efficient manipulation of the magnetization using in. This thesis uses ferromagnetic resonance to explore the currentinduced torques cits in two different systems, namely yigheavy metal bilayers and bulk nimnsb, at room temperature. Part a rank these forces a through f on the basis of the magnitude of the torque they apply to the wrench, measured about an axis centered on the bolt. Metamaterials have recently enabled coupling induced transparency due to interference effects in coupled subwavelength resonators. In the reciprocal process a changing magnetization orientation produces currents that transport spin angular momentum. Transmitted torque analysis of a magnetic gear mechanism. Wong1, so takei2, scott a bender2, murong lang1, jianshi tang1, yaroslav tserkovnyak2, pedram khalili amiri 1 and kang l. All of the elements required by theory9,10 have therefore been separately observed, but spintorque effects in. Currentinduced torques in magnetic materials find, read and. Magnetically induced displacement forces exist for devices consisting of ferro or paramagnetic materials. Pdf currentinduced spinorbit torques in ferromagnetic and.
Methods to manipulate the magnetization of ferromagnets by means of local electric fields 1,2,3 or currentinduced spin transfer torque 4,5,6 allow the design of integrated spintronic devices with. Learn more about the current research into magnetic materials, basic or applied. Induced inverse orderdisorder transition in double. Our xmcd measurements revealed a pressureinduced magnetic transition at 1216 gpa which is independent of temperature within the 40300 k range. We report measurements of current induced torques in heterostructures of permalloy py with tate2, a transitionmetal dichalcogenide tmd material possessing low crystal symmetry, and observe a torque component with dresselhaus symmetry. Wong1, so takei2, scott a bender2, murong lang1, jianshi tang1, yaroslav tserkovnyak2 pedram khalili amiri. Two environmental torques are added to the formulation gravitygradient and magnetic torques. Diluted magnetic semiconductors ga,mnas and ga,mnas,p have been studied. Size dependence of spintorque induced magnetic switching. Current induced spintransfer torques stt and spinorbit torques sot enable the electrical switching of magnetic tunnel junctions mtjs in nonvolatile magnetic random access memories.
Currentinduced spinorbit torque magnetization switching in. We expose the theory of quantized spinpolarized electron transport perpendicular to the plane of a magnetic multilayer with noncollinear magnetization vectors. Novel pressureinduced magnetic transition in magnetite. We apply a microwave current to the sample while sweeping the external magnetic field, and measure the longitudinal dc voltage. In the last 50 years, the behavior of solids without spaceinversion symmetry has been one of the most attractive topics in modern condensed matter physics because they show interesting phenomena such as a variety of magnetoelectric me effects 1 3 and paritymixed superconductivity. Currentinduced torque driven ferromagnetic resonance in magnetic microstructures doctoral thesis. Kent2 and hideo ohno3,4 the magnetization of a magnetic material can be reversed by using electric currents that transport spin angular momentum. Currentinduced magnetization switching using an electrically. Spinorbit torque sot switching of magnetization is a promising. Current induced torques cits on ferromagnetic fm nanoparticles and on domain walls in fm nanowires are normally understood in terms of transfer of conserved spin angular momentum between spinpolarized currents and the magnetic condensate. Jan 10, 2010 methods to manipulate the magnetization of ferromagnets by means of local electric fields 1,2,3 or current induced spin transfer torque 4,5,6 allow the design of integrated spintronic devices with. Journal of magnetism and magnetic materials 320 2008 011.
The stacks consist of magnetic layers, a thin one, which is excited by the spin torque and another, which is typically thicker, to break the inversion symmetry of the layer stack, which is the fixed magnetic layer in the stack. Cofebbased magnetic tunnel junctions with perpendicular magnetic anisotropy are used as a model system for studies of size dependence in spintorqueinduced magnetic switching. Currentinduced switching of perpendicularly magnetized magnetic layers using spin torque from the spin hall effect luqiao liu,1 o. The magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Magnetic multilayer nanopillars for the study of current induced reversal of a thin magnetic layer nathan c.
C inverse of the fmr spintorque generation efficiency 1. The dw was driven in the wire by a 100 ns pulse current. Tunable electromagnetically induced transparency in coupled. Magnetic torques and amps law a magnetic field exerts a force on a straight wire carrying current. Threedimensional analytical calculation of the torque between permanent magnets in magnetic bearings jeroen l. We report the thickness dependence of the dzyaloshinskiimoriya interaction dmi and spinorbit torques sots in pt\cot\alo x, studied by current induced domain wall dw motion and secondharmonic experiments. In this work, we present a three dimensional 3d metamaterial design with sixfold rotational symmetry that shows electromagnetically induced transparency with a strong polarization dependence to the incident electromagnetic wave due. Current induced torques in magnetic materials arne brataas1, andrew d. Currentdriven ferromagnetic resonance, mechanical torques. Torque magnitude ranking task description rank the torques. Exchange coupling torque in ferrimagnetic cogd bilayer maximized. Magnetic torques and amps law rochester institute of.
When a piece of unmagnetised magnetic material touches or is brought near to the pole of a permanent magnet, it becomes a magnet itself. View test prep nature and classification of load torques from drives 2221 at p v polytechnic college. Before weillustrate themathematical physicalmodeldeveloped to evaluate forces and torques, a short description of the magnetic system is given. Temperature dependence of spinorbit torques across the. Abstract full text pdf references request permissions xml. We suggest that the dominant mechanism for this dresselhaus component is not a spinorbit torque but rather the oersted field arising from a component of. Each loop of current has a direction associated with it.
Then, a dw was induced by applying an oppositely weak outofplane magnetic field that is lower than the coercivity but higher than the dw propagation field. Currentdriven spin torque induced by the rashba effect in. Currentinduced magnetic excitations were inferred from currentvoltage i v. Novel pressureinduced magnetic transition in magnetite fe3o4. Request pdf on jul 3, 2012, arne brataas and others published cheminform abstract. Spinorbit torques in nbse2permalloy bilayers nano letters. Numerical and analytical studies of current induced magnetization switching cims and backhopping in mtjs with different thickness of mgo barrier p. Currentinduced ferromagnetic resonance cifmr is an effective method to characterize ferromagnetic samples at micrometrescale and quantify the currentinduced magnetic torques in. Currentinduced torques in magnetic materials find, read and cite all the research you need on researchgate. In this work, we present a three dimensional 3d metamaterial design with sixfold rotational symmetry that shows electromagnetically. Evidence of a new currentinduced magnetoelectric effect. The forces are dependent on the static magnetic field, the gradient in the static fringe field and the.
Sot spearheads novel spintronic applications including high. Barna s ifm pan transdisciplinary cooperation and applications of nanoscience 2122 february 20, cracow. Among the operation methods, currentinduced spinorbit torque. Rank the torques induced by various forces acting on a wrench. The journal of magnetism and magnetic materials provides an important forum for the disclosure and discussion of original contributions covering the whole spectrum of topics, from basic magnetism to the technology and applications of magnetic materials. We report the thickness dependence of the dzyaloshinskiimoriya interaction dmi and spinorbit torques sots in pt\cot\alo x, studied by currentinduced domain wall dw motion and secondharmonic experiments. The gravitygradient can be used to stabilize the satellite such that the satellite is always pointing toward the earth. Threedimensional analytical calculation of the torque. Magnetic multilayer nanopillars for the study of currentinduced reversal of a thin magnetic layer nathan c. Currentinduced torques in magnetic materials request pdf.
Chapter 4 fields and torques in nanomagnetic devices data stored in the free layer of an mtj can be affected by other external. Currentinduced torques in magnetic metals utrecht university. The magnitude of the magnetic eld is 20 mt and a 300 mv rms excitation is applied across a series connection of the 480 sample and a 50 bias resistor. Electronic supporting information files are available without a subscription to acs web editions. Currentinduced magnetic switching with spinorbit torque in an. In addition to the outofplane oersted torque expected from current flow in the metallic nbse2 layer, we also observe an in. Current induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin hall effect luqiao liu,1 o.
The study of spintransfer torques began in 1996 when slonczewski and berger independently predicted that magnetization dynamics can be induced by current in circuits containing noncollinear magnetic elements. Cornell university 2005 this dissertation presents a detailed summary of the nanofabrication of, and measurements performed on, magnetic multilayer nanopillars for the study of current. We suggest that thismagnetic transition isassociated with ahighspinhs to intermediatespin is transition of fe2 ions in the oh. Currentinduced spinorbit torque magnetization switching. Currentinduced torques cits on ferromagnetic fm nanoparticles and on domain walls in fm nanowires are normally understood in terms of transfer of conserved spin angular momentum between spinpolarized currents and the magnetic condensate. Enhancing currentinduced torques by abutting additional spin. C currentinduced magnetization switching curves for the mgocotbpto. In addition to the outofplane oersted torque expected from current flow in the metallic nbse2 layer, we also observe an inplane antidamping torque. Cofebbased magnetic tunnel junctions with perpendicular magnetic anisotropy are used as a model system for studies of size dependence in spintorque induced magnetic switching. Currentinduced torque driven ferromagnetic resonance in magnetic microstructures. Forces can be measured indirectly via a deflection angle generated by the magnetically induced force and the gravity force of the device. From this it was inferred that spin currents could alter the magnetic state of figure 2 currentinduced torque sample geometries. Pdf relativistic torques induced by currents in magnetic.
Evidence of a new currentinduced magnetoelectric effect in a. The use of spinorbit torque sot has attracted much attention as one of the ways to electrically manipulate the magnetization of magnetic thin films by applying an electrical current. Currentdriven ferromagnetic resonance, mechanical torques and rotary motion in magnetic nanostructures. The temperature dependence of spinorbit torques sots and spindependent transport parameters is measured in bilayer tatbco ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy. Currentdriven spin torque induced by the rashba effect in a. Measurement of the spintransfertorque vector in magnetic tunnel junctions jack c. Switching of perpendicular magnetization by spinorbit. Switching of perpendicular magnetization by spinorbit torques in the absence of external magnetic fields guoqiang yu1, pramey upadhyaya1, yabin fan1, juan g alzate1, wanjun jiang1, kin l.
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