Here μ ↑,↓ is the spin-dependent chemical potential and T is the temperature. We use this non-local scheme to separate spin injection from possible spurious effects 6, 11, 12 and because the observed thermally generated non-spin-related voltage, to which we refer as the baseline resistance, enables us to extract the temperature distribution in the device by comparing this with modelling 15. The scheme is essentially a lateral non-local spin-valve structure 6 with the electrical injection replaced by thermal spin injection. The concept of how we generate a heat current over an FM/NM junction and subsequently measure the spin accumulation is shown in Fig. 1. In contrast, the effect we describe in this paper arises from a heat current flowing through a ferromagnetic/non-magnetic metal (FM/NM) junction, which creates a spin accumulation at the interface. 9, which interprets its results in terms of the generation of a bulk spin accumulation due to an applied temperature gradient in a ferromagnetic film. Owing to experimental difficulties in controlling heat flows it was only very recently that thermoelectric spintronics was investigated 19, 20, leading to the new field of spin caloritronics 13. The discovery of the giant magnetoresistance effect 3 sparked the interest of the community in spin-dependent conductivity and new spin electronics that still exists today 4, 5, 8, 18. The interplay of spin-dependent conductivity and thermoelectricity has been known since half a century ago, when it was used to describe the conventional Seebeck effect of ferromagnetic metals 17. We obtain a spin-dependent Seebeck coefficient for Permalloy of −3.8 μV K −1, suggesting that thermally driven spin injection is a feasible alternative for electrical spin injection in, for example, spin-transfer-torque experiments 16.
We studied this new source of spin currents experimentally in a non-local lateral geometry and developed a three-dimensional model that describes the heat, charge and spin transport in this geometry, enabling us to quantify this process 15.
This spin current is generated because, in a ferromagnet, the Seebeck effect-which describes the generation of a voltage as a result of a temperature gradient-is spin dependent 13, 14. Here we demonstrate a conceptually new source of pure spin current driven by the flow of heat across the interface between a ferromagnet and a non-magnetic metal.
In recent years, new sources of pure spin currents (that is, transport of spin angular momentum without charge currents) have been demonstrated 6, 7, 8, 9 and applied 10, 11, 12. Most practical devices 3, 4, 5 use a perpendicular geometry in which the spin currents are accompanied by charge currents. The process is highly scalable, and the material options include all varieties of steels, stainless steels, titanium, nickel super alloys, tungsten alloys, tool steels.Creation, manipulation and detection of spin-polarized carriers are the key elements of spin-based electronics 1, 2. The sintered MIM components display strength characteristics comparable to machined components. During sintering, the remainder of the plastic binder is eliminated, and the metal particles diffuse with each other to form 96-98% dense material without losing its shape integrity. The molded components go through a de-binding process, during which some of the plastic binder is removed, and then they are sintered at high temperatures. In the MIM process, a very fine metal powder is mixed with a little plastic, and then the mix is injection molded into complex shapes utilizing a mold. The presentation also examines how switching to the MIM process can result in a minimum 30% cost reduction for specific applications. The process is metal injection molding – also known as MIM. This 45-minute Webinar discusses a unique process that eliminates the need for complex, expensive machining when producing small, intricate steel and stainless steel components for automotive, Industrial and consumer product applications.
Today’s manufacturing industry requires small & precision parts with high performance and reliability at a competitive cost. This webinar was presented on Tuesday, November 10, 2020