Journal Club Huanlong
Background / Motivation Pt: essential role for generating / detectingpure spin currents Spin Seebeck effect (SSE): a temperature gradient generates a pure spin current in a ferromagnet Spin Hall effect (SHE): a charge current is converted into a spin current via a nonmagnetic metal through its strong spin-orbit coupling Inverse spin Hall effect (ISHE): using a metal with a strong spin-orbit coupling to generate an electric field:  Saitoh et.al., Appl. Phys. Lett. 88, 182509 (2006).  Kimura et. al., Phys. Rev. Lett. 98, 156601 (2007).  Seki et. al., Nature Mater. 7, 125 (2008).  Kato et. al., Science 306, 1910 (2004).  Valenzuela et. al., Nature 442,176 (2006).  K. Uchida et. al., Nature 455, 778 (2008).  K. Uchida et. al., Nature Mater. 9, 894 (2010).  Jaworski et. al., Nature Mater. 9, 898 (2010).  Uchida et. al., Appl. Phys. Lett. 97, 172505 (2010).
Overview • What do they argue? • “A thin Pt film in close proximity with FM YIG relinquishes its nonmagnetic status and acquires FM characteristics.” • “The pure spin current phenomena, such as the inverse spin Hall effect and the spin Seebeckeffect have been contaminated with the anomalous Hall effect and the anomalously Nernst effect, respectively.” • What do they do? • “report magnetotransportstudies, both electric and thermal, of thin Pt films on a FM insulator.” • “observed strong magnetic proximity effects (MPE) with FM characteristics in such Ptthin films as revealed by the thickness dependence of electric and thermal transport in the nanometer (nm) range”
YIG property/Sample structure • yttrium iron garnet (YIG, Y3Fe5O12, TC ≈ 550 K) • YIG: mostly polycrystalline, some epitaxial • rectangular, 3 x 7 x 0.85 mm • magnetically soft, no remnant magnetization • x: 5 mm long and 0.2 mm wide • y: 1 mm long and 0.1 mm wide
AMR Anisotropic magnetoresistance: resistance depends on the directions between the current and the field.
AHE Anomalous Hall effect: extra hall effect that depends on the magnetization direction.
ANE magnetization Anomalous Nernst effect: spin direction