The spin seebeck effect is a spinmotive force generated by a temperature gradient in a ferromagnet that can be detected via normal metal contacts through the inverse spin hall effect k. The inverse spin hall effect converts the injected spin current into a transverse charge voltage, thereby producing. The spin seebeck effect refers to the generation of a spin voltage caused by a temperature gradient in a ferromagnet, which enables the thermal injection of. Experimental proof of the reciprocal relation between spin peltier. We verify for the first time the reciprocal relation between the spin peltier and spin seebeck effects in a bulk yigpt bilayer. Pdf theory of magnondriven spin seebeck effect ken.
In this context, the spin seebeck effect emerges as an attractive candidate for biosensor applications, not only for the sensibility improvement but also for the powersaving electronic devices development. Room temperature and lowfield resonant enhancement of spin. Observation of spin seebeck effect and developmenet in new materials, spanish team. The product of spinmixing conductance and the interfacial spin seebeck coefficient determined is of the order of 108 a m2 k1. Here we show that the spin seebeck effect sse is sensitive to the complexities.
When a thermal gradient is applied across a ferromagnetic material, it can drive a spin current via the spin seebeck effect. We develop a lowtemperature, longwavelength theory for the interfacial spin seebeck effect sse in easyaxis antiferromagnets. Pdf origin of the spin seebeck effect in compensated. Origin of the spin seebeck effect in compensated ferrimagnets. Using the spin seebeck effect sse, it is possible to create a current of pure spin a quantum property of electrons related to its magnetic moment in magnetic insulators. The spin wave current, transmitted through a y 3 fe 5 o 12 micro cantilever, was found to create a mechanical force on the cantilever as a nonlocal reaction of the spin seebeck effect. This technology employs the concept of the seebeck effect which involves the interaction between. Seebeck and peltier effects university of mississippi. We theoretically consider the spin seebeck effect, the charge seebeck coefficient, and the thermoelectric figure of merit in. By using the spin seebeck effect, the generation of an electric voltage from a heat gradient is demonstrated for the first time in an insulator. A bilayer of a polycrystalline pt and an epitaxiallystrained cfo110 exhibiting an inplane uniaxial anisotropy was prepared by reactive rf sputtering technique. Spin thermoelectric effects in organic singlemolecule devices. New spin seebeck thermoelectric device with higher conversion efficiency created. Spinseebeck and anomalous nernst effects in mnbi and bi.
The longitudinal spinseebeck effect lsse has been investigated in cobalt ferrite cfo, an exceptionally hard magnetic spinel ferrite. The recently discovered inversespinhall effect 10,11,12,14 ishe is a powerful tool for detecting spin voltage, and we use it to. The spin seebeck effect sse refers to the generation of a spin current as a result of a temperature gradient in magnetic materials including insulators. From the curves of spinup currents, we find there is no threshold temperature, and the spinup currents increase rapidly at. The spinseebeck effect sse converts a heat current into a spin current, a flow of spin angular momentum, and spin voltage, the driving force for nonequilibrium spin currents, in a ferromagnetic metal. The spin seebeck effect refers to the generation of spin voltage as a result of a temperature gradient in ferromagnetic or ferrimagnetic materials.
The thermoelectric conversion technique has been explored in a broad range of heatflow sensors. To realize the sse together with high spin thermoelectric conversion efficiency tce, two nanoscale structures referred to as nanoribbons and nanotubes have. Spin seebeck effect in layered ferromagnetic insulators. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Theory of spin seebeck effect, saitoh group imr, tohoku university, sendai.
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. Modulating the spin seebeck effect in co2feal heusler. Experimental details of the spin seebeck effect 5 5. Peltier effect 1834 the reverse of the seebeck effect is also possible. The seebeck effect occurs when a voltage is induced by a temperature difference between the two terminals of a sample. Pdf the spin seebeck effect is observed when a thermal gradient applied to a spinpolarized material leads to a spatially varying. The spin seebeck effect sse, referring to thermal spincurrent generation in a magnet, may provide new mechanisms for solidstate thermaltoelectrical energy conversion with applications for waste heat recycling and temperature sensors. Here we report the observation of the thermal generation of driving power, or voltage, for electron spin. A few years ago, it was shown that this effect also works in ferromagnetic insulators where the charge degree of freedom is strongly gapped. Download highres image 92kb download fullsize image. The spinseebeck effect sse has been regarded as one of the core topics in spin caloritronics. Spin seebeck effect and thermal colossal magnetoresistance in.
Broadband optical detection using the spin seebeck effect. When a conductor is attached to a magnet under a temperature gradient, the thermally generated spin voltage in the magnet injects a spin current into the. The spin seebeck effect refers to the generation of a spin voltage caused by a temperature gradient in a ferromagnet, which enables. Possibilities in thermoelectric conversion using a new. Pdf length scale of the spin seebeck effect caroline. This is due to the electrons that move from the hot side to the cooler one.
Pdf observation of the spinseebeck effect in a ferromagnetic. Spin seebeck mechanical force nature communications. The spin seebeck effect sse converts thermally induced magnetization dynamics in magnetic materials to spin currents, but is so far an. In a temperature gradient, the flux of magnons in the fm transfer spin angular momentum to the electrons in the nm, which, by the ishe contributes an sse voltage. The lsse response is clearly observed in the ferromagnetic phase andin contrast to a standard lsse magnet y. This spin effect is based on the original seebeck effect, discovered in the 1800s by johann seebeck, which consists in the phenomenon of voltage apparition between two unequallyheated ends of a conducting rod. The spinwave current, transmitted through a y 3 fe 5 o 12 micro cantilever, was found to create a mechanical force on the cantilever as a nonlocal reaction of. Theory of the spin seebeck effect fb physik, fu berlin. The spindependent seebeck effect sdse is one of the core topics of spin caloritronics. Seebeck in the 1820s, which is described as the generation of an electric voltage as a result of a temperature gradient.
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. We study the spinseebeck effect in a strongly interacting, twocomponent fermi gas and propose an experiment to measure this effect by relatively displacing. Spin seebeck effect spintronics for next generation. The impact of the zeeman gap in nonlocal spin seebeck effect.
Spin seebeck and spin peltier effects sadamichi maekawa advanced science research center. The spin seebeck effect, the generation of a spin current by a temperature gradient, has attracted great attention, but the interplay over a millimetre range along a thin ferromagnetic film as well as unintended side effects which hinder an unambiguous detection have evoked controversial discussions. When the sample is a ferromagnet or a magnetic multilayer, the seebeck coefficient depends on spin. Here, we utilize the spin seebeck effect sse in pty3fe5o12 devices to detect light from 390 to 2200 nm. Spinseebeck effect in a strongly interacting fermi gas. Here, we investigate the longitudinal spin seebeck effect in films with a co 2 fealw. Typically when referring to electrical current, an image of electrons moving through a metallic wire is conjured. Junichiro inoue, in nanomagnetism and spintronics second edition, 2014. Since the discovery of the spin seebeck effect sse in 2008, it has become one of the most active topics. Spin thermoelectric effects in organic singlemolecule. How to realize a spindependent seebeck diode effect in. This process was discovered in 1834 by scientist named peltier, and thus it is called the peltier effect.
The spinseebeck effect sse is an advective transport process in a bilayer composed of a ferromagnet fm and a nonmagnetic nm material with strong spinorbit coupling. We have studied the longitudinal spin seebeck effect lsse in the layered ferromagnetic insulators crsite. Investigation of the spin seebeck effect and anomalous nernst effect. This is the socalled spin seebeck effect that generates spin current. When a conductor is attached to a magnet under a temperature gradient, the thermally generated spin voltage in the magnet injects a spin current into the conductor, which in turn produces electric voltage owing to the spinorbit interaction. Recent theoretical and experimental efforts have shown that the magnon and phonon degrees of freedom play crucial roles in the spin seebeck effect. Local picture of thermal spin injection by magnons 5 5. Paramagnetic spin seebeck effect argonne national laboratory. Picosecond spin seebeck effect university of illinois at. The spin seebeck effect is a spin motive force generated by a temperature gradient in a ferromagnet that can be detected via normal metal contacts through the inverse spin hall effect k. Spin seebeck effect and thermoelectric phenomena in. 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. Spinpolarized transport and spin seebeck effect in triple.
Ab we report timeresolved magnetooptic kerr effect measurements of the longitudinal spin seebeck effect in normal metaly3fe5o12 bilayers driven by an interfacial temperature difference between electrons and magnons. Pdf giant spin seebeck effect in a nonmagnetic material. The effect can be exploited, for example, in thermal electricpower generators and for temperature sensing, by connecting two conductors with different seebeck coefficients, a device called a thermocouple. Pdf broadband optical detection using the spin seebeck. Thermal spin transport properties of christmastree silicene nanoribbons csinrs.
Below sf, there are two spin carriers with opposite magnetic moments, with the carriers polarized along the field forming a majority magnon band. This may sound similar to joule heating described above, but in fact it is not. The inverse spin hall effect converts the injected spin current into a transverse charge voltage, thereby producing electromotive force as in the conventional charge seebeck device. The spinseebeck effect was recently discovered in a metallic ferromagnet and. This stands in contrast with the spin seebeck effect sse, which stands for the generation of spin voltage as a result of a temperature gradient. In the paramagnet, the spin current is converted into an electric field due to the invserse spin hall effect. The large spin seebeck coefficient appears at a transition temperature from the ballistic resonant to tunneling regimes. Theory of the spin seebeck effect internet archive.
The observed behavior cannot be explained as an interface effect or by variations of the material parameters. This chapter begins with a discussion of the seebeck effect discovered by t. This socalled spin seebeck effect, which is also detected in ferromagnetic semiconductor and magnetic insulator. This is an obvious spin seebeck effect since the spinup and spindown currents flow in opposite directions, which are generated only from a temperature gradient 10,11,34. The spin seebeck effect is a spin motive force generated by a temperature gradient in a ferromagnet that can be. The amplitude of the spinseebeck effect in gamnas scales with the thermal conductivity of the gaas substrate and the phonondrag contribution to the thermoelectric power of the gamnas, demonstrating that phonons drive the spin redistribution. However, this spin seebeck effect remains to be observed. Thermoelectric generation based on spin seebeck effects. Thus, the spin seebeck effect sse is detected through the inverse spin hall effect in heavy metal pt. The spin current is then induced in the paramagnetic transition metal tm, and converted into an electrical current by means. Of particular interest is the spin seebeck effect sse that generates pure spin current without the accompany of the charge counterpart, or spin bias characterized by the splitting of spinup and spindown chemical potentials. The sse is applicable to thermoelectric generation because the thermally generated spin current can be converted into a charge current via spinorbit interaction in conductive materials adjacent to the magnets. The spin seebeck effect is not only observed in ferromagnetic metal, but also in ferromagnetic semiconductor and. Gilbert llg phenomenology for describing the magnetization dynamics, the spin.