The spin seebeck effect sse has long been considered as an effective route to generate pure spin currents by using a temperature gradient in magnetic materials. Spindependent seebeck effect leads to spin polarized current. Complex terahertz and direct current inverse spin hall effect. Publishers pdf, also known as version of record includes final page, issue and volume numbers. When a temperature difference is applied across the device, the electrons or holes with different spin index flows at almost the same rate in the opposite direction were derived, and a perfect seebeck effect is observed. Employing the boltzmann and landauer formalisms we calculate the spin and charge seebeck coefficients thermopower in magnetic graphene varying the spin splitting, temperature, and doping of the junction. Spindependent seebeck effect and spin caloritronics in magnetic.
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. Chien1, 1department of physics and astronomy, johns hopkins university, baltimore, maryland 21218, usa 2department of physics, national tsing hua university, hsinchu 300, taiwan 3department of physics and astronomy, university of california, irvine, california 92697, usa. The recently discovered inverse spin hall effect 10,11,12,14 ishe is a powerful tool for detecting spin voltage, and we use it to. When the sample is a ferromagnet or a magnetic multilayer, the seebeck coefficient depends on spin. The thermal generation of a spin current and an associated spin voltage is known as the spin 47 or spin dependent 48 seebeck effect we will stick with the former notation in this manuscript. We investigate the spindependent thermoelectric effects in magnetic graphene in both diffusive and.
Complex terahertz and direct current inverse spin hall. Conversely, when a voltage is applied to it, heat is transferred from one side to the other, creating a temperature difference. The relevant spins are effective only in the magnetically ordered state and are mainly due to spatially localized electrons. Spindependent seebeck effect, and spinfiltering and. Spindependent seebeck effect in nonlocal spin valve devices. Klauia institut fur physik, johannes gutenberguniversitat mainz, 55099 mainz, germany abstract the temperature dependent longitudinal spin seebeck effect sse in heavy metal hmy 3 fe 5 o 12. The spindependent seebeck effect and the spindependent seebeck diode appeared in the zigzag edge. Similarly, the spindependent thermoelectric effects exploit the fact that the seebeck coefficients for spinup and spindown electrons, s and s v, are also different because of the exchange splitting of the dband 16, 17.
Spin caloritronics spindependent seebeck effect single particle spin seebeck effect collective spin caloritronics thermodynamic analysis of interfacial transport and of the thermomagnetoelectric system mark johnson and r. We report the observation of the spin nernst effect in w. Spindependent seebeck effect and spin caloritronics in. Magnetoseebeck tunneling is a spindependent generalization of the purely thermoelectric tunneling seebeck effect. These thermal effects also provide the opportunity to create a pure spin current from thermal gradients via a mechanism call the spin dependent seebeck effect sdse. Magnon polarons in the spin seebeck effect citation for published version apa. Spin transport across antiferromagnets induced by the spin. Spindependent seebeck effect in aharonovbohm rings with rashba and dresselhaus spinorbit interactions bin liua, yunyun lia, jun zhoua,n, tsuneyoshi nakayamaa,b, baowen lic a center for phononics and thermal energy science, school of physics science and engineering, tongji university, shanghai 200092, peoples republic of china b hokkaido university, sapporo 0600826, japan. The transient spin seebeck experiments, which will be presented in this thesis, contribute to the ongoing discussion outlined above. Giant enhancement in rashba spinseebeck effect in nifep. N2 the coupling of spin and heat gives rise to new physical phenomena in nanoscale spin devices. Giant enhancement in rashba spinseebeck effect in nifepsi. Spindependent seebeck effect sdse is one of hot topics in spin caloritronics, which examine the relationships between spin and heat.
Introduction the spin seebeck effect sse describes the phenomenon that spin currents can be thermally excited. Here it is important to point out the fundamental difference between the spindependent seebeck and the so called spin seebeck effect 11 whereas the. I find that the heat current and spindependent seebeck coefficient can be controlled by thickness of the heat sink layer and composition of fm, respectively. After the charge seebeck and peltier effects are introduced, we present spindependent charge and. Junichiro inoue, in nanomagnetism and spintronics second edition, 2014. Thermoelectric devices create a voltage when there is a different temperature on each side.
Influence of thickness and interface on the lowtemperature enhancement of the spin seebeck effect in yig films erjia guo,1,2 joel cramer,1 andreas kehlberger,1 ciaran a. Pdf spindependent seebeck effect, thermal colossal. Known phenomena are classified either as independent electron such as spin dependent seebeck effects in metals that can be understood by a model of two parallel spin transport channels with. The spin nernst effect in tungsten science advances. In the traditional device designs of spin dependent seebeck rectifiers and diodes, finite spin dependent band gaps of materials are required to realize the onoff characteristic in thermal spin currents, and nearly zero. Sharp structures in the magnetic fielddependent spin seebeck effect sse. Spin dependent seebeck effect, thermal colossal magnetoresistance and negative differential thermoelectric resistance in zigzag silicene nanoribbon heterojunciton.
In the traditional device designs of spindependent seebeck rectifiers and diodes, finite spindependent band gaps of materials are required to realize the onoff characteristic in thermal spin currents, and nearly zero. Giant enhancement in rashba spinseebeck effect in nifepsi thin films ravindra g. Spin seebeck effect and thermoelectric phenomena in. Theory of spin seebeck effect, saitoh group imr, tohoku university, sendai. Metalfree magnetism, spindependent seebeck effect, and spin. Furthermore, the spin up and spin down currents with opposite directions, generated by a temperature gradient, are almost symmetrical, indicating the appearance of the perfect spin dependent seebeck effect sdse.
Here it is important to point out the fundamental difference between the spindependent seebeck and the so called spin seebeck effect 11 whereas the spindependent seebeck effect is purely electronic. Since anomalous nernst and spin seebeck e ect hinge on fundamentally di erent microscopic processes, both e ects could be distinguished by time resolved measurements. We report temperature dependent measurements of the spin seebeck effect sse in multilayers formed by repeated growth of a fe3o4pt bilayer junction. Particular attention is paid on the generation and manipulation of the 100% spin polarized and pure spin thermopowers, which denote the arisen spin voltage in response of. Positive currents show higher polarization of spin injection than negative. Its basis is the temperaturedriven spinpolarized tunneling of electrons in a magnetic tunnel junction mtj where the temperature t drops by. Spinorbit interactions and aharonovbohm effect determine the spin seebeck coef. Ultrafast heat conduction can manipulate nanoscale magnets. For the zigzag edge, when a temperature gradient was produced between two electrodes, the spinup and spindown currents were driven in opposite directions, which indicated the appearance of the spindependent seebeck effect sdse. The peltier effect can be considered as the backaction counterpart to the seebeck effect analogous to the backemf in magnetic induction. The seebeck coefficient also known as thermopower, thermoelectric power, and thermoelectric sensitivity of a material is a measure of the magnitude of an induced thermoelectric voltage in response to a temperature difference across that material, as induced by the seebeck effect.
The longrange spin seebeck effect is beyond the traditional spin caloritronics concept proposed by johnson and silsbee. Direct observation of the spindependent peltier effect j. The thermal spin filtering effect appeared in the armchair edge. Spin current is parallel to the temperature gradient in lsse24 while it is perpendicular to the temperature gradient in tsse9, 2526. Spin heat accumulation and spindependent temperatures in. Recently, the spin seebeck effect sse 1,2,3,4 has attracted much attention, due to open fundamental physics questions 1,2,3,5,6,7,8,9,10,11,12, and also because of the potential for practical applications 14.
The large spin seebeck coefficient appears at a transition temperature from the ballistic resonant to tunneling regimes. Since anomalous nernst and spin seebeck e ect hinge on fundamentally di erent microscopic processes, both e ects could be distinguished by time. The discovery of the spin dependent seebeck effect sdse, where thermal gradients over a bulk fm 2 or across an interface to a normal metal 3 generate scs, opened a path towards overcoming such limitations. Spindependent seebeck effect and spincaloritronics in. In the spin hall effect she, a charge current driven by a voltage gradient can generate a transverse spin current 1. Signature of spindependent seebeck effect in dynamical spin. Influence of thickness and interface on the lowtemperature. An experiment reported in 2008 put a new twist on spin caloritronics, because understanding of that experiment. This implies that in addition to currentinduced spin injection, there is a thermally induced injection from a spindependent seebeck effect. Origin of the thicknessdependent lowtemperature enhancement. We study the spin dependent electronic and thermoelectric transport through a structure composed of triple quantum dots tqds coupled to two metallic leads in the presence of spin dependent interdot couplings, which is reliable by applying a static magnetic field on the tunnel junctions between different dots. The magnetic and thermal spin transport properties of nitrophenyl diazonium functionalized graphene sheets were presented. Various spindependent electrical and thermal phenomena in metallic.
By substituting some boron or nitrogen atoms with carbon atoms in boronnitrogen nanotubes bnnts, we constructed some magnetic bnnt heterojuncti. Direct observation of the spindependent peltier effect. The spin hall effect allows the generation of spin current when charge current is passed along materials with large spin orbit coupling. The interfacial spin generation rate is proportional to the heat current through fm and spindependent seebeck coefficient of fm. T1 thermal spintransfer torque driven by the spindependent seebeck effect in metallic spinvalves. T1 thermal spin transfer torque driven by the spin dependent seebeck effect in metallic spin valves. Spin orbit interaction, spin dependent seebeck effect, aharonovbohm. B 35, 4959 1987 name alternative name subject electronics control of charge transport. When the tqds are serially connected, a 100 % spin polarized conductance and.
Within the quasiclassical approximation, only particles with energies close to the fermi surface are assumed to contribute to transport, and the green. Spin seebeck effect in a multiple quantum dot molecule with. Spinpolarized transport and spin seebeck effect in triple. The spindependent seebeck effect sdse is one of the core topics of spin caloritronics. Thermal spin transfer torque driven by spindependent seebeck effect in metallic spinvalve structures gyungmin choi1,2, chulhyun moon 2,3, byoungchul min, kyungjin lee3,4, and david g.
Jan 31, 2017 the thermal generation of a spin current and an associated spin voltage is known as the spin 47 or spin dependent 48 seebeck effect we will stick with the former notation in this manuscript. Effect of magnetic anisotropy on spindependent thermoelectric effects in nanoscopic systems maciej misiorny 1,2 3 and jozef barna. Temperature dependence of the spin seebeck effect in. In this work, we use the lsse configuration to discover the spin mediated. The seebeck effect occurs when a voltage is induced by a temperature difference between the two terminals of a sample. Magnetoseebeck tunneling on the atomic scale science. Spin seebeck effect a variety of spin seebeck devices. We measure the inverse spin hall effect of cu1xirx thin films on yttrium iron garnet over a wide range of ir concentrations 0. It is now widely accepted that the thermopower signals measured in ferromagnetic insulatornormal metal fminm bilayers in the longitudinal sse geometry are indeed a consequence of. Spindependent seebeck effect, spindependent seebeck. We study the spindependent electronic and thermoelectric transport through a structure composed of triple quantum dots tqds coupled to two metallic leads in the presence of spindependent interdot couplings, which is reliable by applying a static magnetic field on the tunnel junctions between different dots. The spin dependent seebeck effect and the spin dependent seebeck diode appeared in the zigzag edge. We study the spin seebeck effect in a circularly connected triple quantum dot tqd structure taking the spin dependent interdot coupling and magnetic flux into consideration. Femtosecond spincurrent pulsesgenerated by thenonthermalspin.
In the traditional device designs of spindependent seebeck rectifiers and diodes, finite spindependent band gaps of materials are required to realize the onoff characteristic in thermal spin currents, and nearly zero charge current should be achieved to reduce energy dissipation. Coupling of heat and spin currents in metallic multilayers. Femtosecond spin current pulses generated by the nonthermal spindependent seebeck effect and interacting with ferromagnets in spin valves. Spindependent seebeck effect in nonlocal spin valve.
Temperature dependence of the spin seebeck effect in fe3o4. Spin currents are triggered through the spin seebeck effect, either by a continuous dc temperature gradient or by ultrafast optical heating of the metal layer. Length scale of the spin seebeck effect andreas kehlberger,1, ulrike ritzmann,2 denise hinzke,2 erjia guo,1 joel cramer,1 gerhard jakob,1 mehmet c. We develop a simple theory for the spindependent seebeck effect in ndoped insb in an external magnetic. Moreover, thermally driven spin currents through the nanodevices induced the spin seebeck diode ssd effect. Pdf giant spin seebeck effect in a nonmagnetic material.
Bhardwaj1, paul c lou1 and sandeep kumar1,2 1 department of mechanical engineering, university of california, riverside, ca 92521, usa 2 materials science and engineering program, university of. Observation of spin seebeck effect and developmenet in new materials, spanish team. Maximum spin seebeck coefficient can be s obtained when the strengths of rashba and dresselhaus spinorbit couplings are slightly different the spin seebeck coefficient can be reduced by increasing. The sse is in fact the combination of two effects, a magnonic spin current in the magnetic material induced by the temperature. The spin seebeck effect refers to the generation of a spin voltage caused by a temperature.
Spindependent seebeck effect in aharonovbohm rings with. Use an inplane magnetic layer of cofeb as a ballistic pendulum for the spin current spin current kicks magnetization of cofeb outofplane spin torque and induces precession. Due to the challenges in control and measurement of thermal gradients in nanoscale structures, both the fundamental physics and materials dependencies of thermallydriven spin. The spin dependent seebeck effect sdse is one of the core topics of spin caloritronics. Klauia institut fur physik, johannes gutenberguniversitat mainz, 55099 mainz, germany. Pdf the spin seebeck effect is observed when a thermal gradient applied to a spinpolarized material. When the tqds are serially connected, a 100 % spinpolarized conductance and. The magnitude of the observed enhancement of the sse, relative to the sse in the single bilayer, shows a monotonic increase with decreasing the temperature. Picosecond spin caloritronics david cahill, johannes kimling, and gyungmin choi department of materials science and engineering. We consider spin1 2 electrons in the conduction band of insb with a temperature gradient parallel to the.
The spin hall current is detected by electrical contacts or measurement of the. Spindependent thermoelectric effects in graphene based spin. Cahill1 1department of materials science and engineering and materials research laboratory, university of illinois, urbana, illinois 61801, usa. Thermal spin transfer torque driven by spin dependent seebeck effect in metallic spin valve structures gyungmin choi1,2, chulhyun moon 2,3, byoungchul min, kyungjin lee3,4, and david g.
It has been recently predicted that heat current in a nonmagnetic metal can be converted into spin current via a process referred to as the spin nernst effect. Thermal spintransfer torque driven by the spindependent. Spindependent seebeck effect in aharonov bohm rings with. University of groningen thermoelectric effects in magnetic. It should be noted that these magnon or spinrelated effects are based on thermally nonequilibrium spin currents. Bin liu,a yunyun li,a jun zhou,a, tsuneyoshi nakayama,a,b and baowen lic. University of groningen spin caloritronics in magneticnon. This result can be understood by an increase of the characteristic length for spin.
Spindependent seebeck effect, spindependent seebeck diode. Origin of the thicknessdependent lowtemperature enhancement of spin seebeck effect in yig films e. This implies that in addition to currentinduced spin injection, there is a thermally induced injection from a. Pdf spindependent seebeck effect sdse is one of hot topics in spin caloritronics, which examine the relationships between spin and heat transport. The recently discovered inversespinhall effect 10,11,12,14 ishe is a powerful tool for detecting spin voltage, and we use it to. Detect spin accumulation and magnetization dynamics by timeresolved magnetooptic kerr effect trmoke. We investigate the spin dependent thermoelectric effects in magnetic graphene in both diffusive and ballistic regimes. Spindependent seebeck effect in metallic nanopillar spin valves lateral spin valve devices using a 3dfem. Spindependent seebeck effect, and spinfiltering and diode effects. May 21, 2012 above a critical current, there is an unexpected dependence of spin injection on current direction. Signature of spin dependent seebeck effect in dynamical spin injection of metallic bilayer structures to cite this article. However, this spin seebeck effect remains to be observed. The 3d ferromagnetic metals exhibit relatively large diffusion thermopowers because of the pronounced structure of.