Magnetization dynamics induced by spinorbit torque. In the frequency range close to the natural resonance frequency of the magnetic moments gigahertz, cit can excite precessional motion of the magnetisation, a process. Slonczewskis observation that a net spin current flux into a volume of magnetic material implies that a torque acts on the magnetization in that volume is the key idea for most theories of current induced torques cits. In sot devices, spincurrent that is generated by spin hall e. Stiles 1center for nanoscale science and technology, national institute of standards and technology, gaithersburg, maryland 208996202, usa 2pctp and department of physics, pohang. Currentinduced magnetization switching magnetism and. Interfaceenhanced spinorbit torques and currentinduced. Wong 1, so takei 2, scott a bender2, lite chang1, ying jiang 3, murong lang1, jianshi tang 1, yong wang 3, yaroslav tserkovnyak 2, pedram khalili amiri 1 and kang. We report measurements of currentinduced 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. These torques are most commonly termed adiabatic and nonadiabatic, respectively 1116, and the parameters z and b characterize their strength. Kent2 and hideo ohno3,4 the magnetization of a magnetic material can be reversed by using electric currents that transport spin angular momentum. 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. Current perspectives currentinduced domain wall motion. An additional advantage of the switching method discussed here is that currentinduced magnetic writing is efficient also for hard magnetic layers due to the builtin spinorbit coupling of many of these materials.
The experimental discovery of a rashbatype torque in an fm metal at room temperature opens very promising perspectives in spintronics, namely for the fabrication of magnetic storage and logic gates operating through intrinsic currentinduced so torques. Current induced torques in the presence of spinorbit coupling. Journal of magnetism and magnetic materials 320 2008 11901216 current perspectives spin transfer torques d. In addition to the outofplane oersted torque expected from current flow in the metallic nbse2 layer, we also observe an inplane antidamping torque.
Currentinduced torques in magnetic materials arne brataas1, andrew d. Currentinduced spinorbit torques mediate the transfer of angular momentum from the lattice to the spin system, leading to. Journal of magnetism and magnetic materials 320 2008 011 current perspectives currentinduced torques in magnetic metals. Currentinduced magnetization switching using an electrically insulating spintorque generator hongyu an,1 takeo ohno,2,3 yusuke kanno,1 yuito kageyama,1 yasuaki monnai,1 hideyuki maki,1,3 ji shi,4 kazuya ando1,3 currentinduced magnetization switching through spinorbit torques is the fundamental building block of spin. In this article we develop a theory for current in duced torques both spin transfer torques and mechanical torques in systems with strong spinorbit. Louis smith summary one of the sources of torques on nearearth satellites is the interaction of the earths magnetic field with eddy currents induced in the electrically conducting parts of a spinning satellite. First, the materials and structural engineering that enhances sot efficiency are discussed. The manipulation of magnetic order, domain walls and skyrmions by spinorbit torques provides evidence of the microscopic interactions between charge and spin in a variety of materials and opens novel strategies to design spintronic devices with potentially high impact in data storage, nonvolatile logic, and magnonic applications.
An electron spin interacts with the magnetization of a thin. 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. Currentinduced magnetization switching in ptcota with interfacial decoration by insertion of cr to enhance perpendicular magnetic anisotropy and spin orbit torques to cite this article. Pdf currentinduced spinorbit torques in ferromagnetic. Current induced torques in magnetic materials arne brataas1, andrew d. H, which arises from the mixing of the ac current with the hall effect modulated by the oscillations of the magnetization induced by the dl and fl torques 1416,27,28. Recent theoretical work suggests that currentinduced spinorbit effects detected in nonmagnetic semiconductors 20 could be used in combination with. Currentinduced effects are characterized by measuring the second harmonic hall resistance, r2.
Currentdriven spin torque induced by the rashba effect in. Relativistic torques induced by currents in magnetic materials. Buhrman1 1cornell university, ithaca, new york 14853, usa 2kavli institute at cornell, ithaca, new york, 14853 received 24 april 2012. Selfcurrent induced spinorbit torque in femnpt multilayers. Universal chiraltriggered magnetization switching in confined nanodots universal chiraltriggered magnetization switching in confined nanodots. However, to use 2d vdw magnets for building spintronic nanodevices such as magnetic memories, key challenges remain in terms of effectively switching the magnetization from one state to the other electrically. Measurements of the propagation field and the energy barrier for thermally activated dw motion reveal a large currentinduced torque equivalent to an outofplane magnetic field of.
By changing the current pulse forms through the device, the four magnetic state memory was demonstrated. Currentinduced torques in magnetic materials nature. Macdonalda adepartment of physics, the university of texas at austin, austin, tx 787120264, usa. Journal of magnetism and magnetic materials 320 2008 011. Currentdriven domain wall dw motion is investigated in ptcogdox nanostrips with perpendicular magnetic anisotropy. Currentinduced switching of perpendicularly magnetized. Switching of perpendicular magnetization by spinorbit torques in the absence of external magnetic. 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. Pdf spinorbit torques induced magnetization reversal and domain. By controlling the magnetization orientation through the interplay of magnetocrystalline. Relativistic torques induced by currents in magnetic.
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. Effects of magnetically induced eddycurrent torques on spln motions of an mm satellite by g. Pdf relativistic torques induced by currents in magnetic. 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 torques in ferromagnetic and. Currentinduced torques in magnetic materials request pdf. Currentinduced magnetization switching main content. Currentinduced torque driven ferromagnetic resonance in. Tunable chiral spin texture in magnetic domainwalls tunable chiral spin texture in magnetic domainwalls. In the frequency range close to the natural resonance frequency of the magnetic. The memory device contains two co layers with different perpendicular magnetic anisotropy, separated by a spacer layer of pt. Currentinduced switching of perpendicularly magnetized magnetic layers using spin torque from the spin hall effect luqiao liu,1 o. In the absence of currentinduced torques, this outofplane con.
Express 11 001 view the article online for updates and enhancements. The combined effect of spinorbit coupling and exchange interaction permits the alternating current to induce an oscillating currentinduced torque cit on the magnetisation. The device for the currentinduced magnetization switching using an electrically insulating spintorque generator is a mgo 1. The divergence of the spin current corresponds to a change of magnetization. Currentinduced fourstate magnetization switching by spin.
Bender2,litechang1, ying jiang3, murong lang1,jianshitang1, yong wang3, yaroslav tserkovnyak2, pedram khalili amiri1 and kang l. We demonstrated currentinduced fourstate magnetization switching in a trilayer system using spinorbit torques. Currentinduced spin torques in iiiv ferromagnetic semiconductors dimitrie culcer,1,2 m. Pdf currentinduced spinorbit torques in ferromagnetic and. Making use of the opposite spin current at the top and bottom surface of the middle pt layer, magnetization of both co layers can be switched oppositely by the spinorbit torques with different critical switching currents. Current induced effective field h frequency 500 hz h. So far, the quantitative determination of charge currentinduced spin current and spinorbit torques sots on the magnetic layer adjacent to twodimensional materials is still lacking. Currentinduced spinorbit torques in ferromagnetic and antiferromagnetic systems. Pdf spin orbit torques in magnetic materials kiran sethu. Currentdriven spin torque induced by the rashba effect in a ferromagnetic metal layer. Switching of perpendicular magnetization by spinorbit.
Current inplane field transverse to i hall voltage v h current induced h measuring v out gives information on the current induced effective field h effective field measurements2000 0 20001. To measure the currentinduced torques in our samples, we use two complementary measurement methods, a harmonic hall technique,11,21,22 and spintorque ferromagnetic resonance stfmr,2,6,10 with all measurements made at room temperature. 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. Currentinduced torques with dresselhaus symmetry due to. Current induced spinorbit torques mediate the transfer of angular momentum from the lattice to the spin system, leading to sustained. Roles of joule heating and spinorbit torques in the direct current induced magnetization reversal. Currentinduced torques in magnetic metals utrecht university. To further confirm the magnetization reversal mechanism, we also summarize h sw against the angle. Effects of magnetically induced eddycurrent torques on. Spin orbit torques and current induced domain wall motion. Currentinduced magnetization switching in ptcota with.
In the reciprocal process a changing magnetization orientation produces currents that transport spin angular momentum. Stilesb alaboratory of atomic and solid state physics, cornell university, ithaca, ny 14853, usa bcenter for nanoscale science and technology, national institute of standards and technology, gaithersburg, md 208996202, usa. Here, we report a large sot generated by currentinduced spin accumulation through the rashbaedelstein effect in the composites of monolayer tmd mos 2 or. The interaction of spin polarized conduction electron with the magnetization of a ferromagnetic material. A large amount of work has been dedicated to identifying materials with large soc to generate giant spin currents for magnetization switching. Bergers paper focused on the emission of spin waves as the source of magnetic excitations, while slonczewski invoked conservation of spin angular momentum to.
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