Magneto-optical Kerr spectra of gold induced by spin accumulation

Abstract

We report the magneto optic Kerr effect (MOKE) angle of Au magnetically excited by spin accumulation. We perform time resolved polar MOKE measurements on Au/Co heterostructures. In our experiment, the ultrafast optical excitation of the Co drives spin accumulation into an adjacent Au layer. The spin accumulation, together with spin-orbit coupling, leads to non-zero terms in the off-diagonal conductivity tensor of Au, which we measure by recording the polarization and ellipticity of light reflected from the Au surface for photon energies between 1.3 and 3.1 eV. In a narrow energy range near the interband transition threshold of Au, the sensitivity to magnetization measured exceeds 1 µrad per A/m. In the photon energy interval of 0.6 -4.4 eV, the maximum value for transition ferromagnetic metals like Ni are < 10 nrad per A/m, while predicted values for heavy metals like Pt or W are < 13 nrad per A/m. The exceptional sensitivity of the optical properties of Au to spin magnetic moments make Au to be an exceptionally sensitive optical magnetometer, with potential applications in the development of optospintronic technologies.

Spin current driven by ultrafast magnetization of FeRh

“…The electronic contribution to the angular momentum dissipation was revealed from the spin dynamics in heterostructures: ultrafast demagnetization of FM generates a transient spin current in a non-magnetic metal (NM). Ultrafast-demagnetization-driven spin currents have been con rmed by various experimental observations, such as spin accumulation on NM in FM/NM [9][10][11][12][13] , terahertz generation from NM in FM/NM [14][15][16][17] , coupling of demagnetization dynamics of FM in FM/NM/FM with a collinear magnetization of the FM pair [18][19][20] , and spin-transfer-torque on FM in FM/NM/FM with a non-collinear magnetization of the FM pair 21,22 . However, a theoretical interpretation of the spin current remains controversial 9,10,[23][24][25] .…”

Electroless Cobalt Deposition on Dealloyed Nanoporous Gold Substrate: A Versatile Technique to Control Morphological and Magnetic Properties

“…In recent decades, the electrodeposition of Co thin film on continuous Au electrodes has been extensively investigated for its wide-range synergistic or complementary physical and chemical properties which constitute the core of interesting scientific studies and applications [ 24 , 25 , 26 , 27 , 28 ].…”