Long-range transverse spin Seebeck effect in permalloy stripes using Sagnac interferometer microscopy

Abstract

Coupling of spins and phonons in ferromagnets (FM) may persist up to mm length scale, thus generating macroscopic spatially distributed spin accumulation along the direction of an applied thermal gradient to a FM slab. This typical feature of transverse spin Seebeck effect (TSSE) has been demonstrated so far using electrical detection methods in FM films, in particular in a patterned structure, in which FM stripes grown onto a substrate perpendicular to the applied thermal gradient direction are electrically and magnetically isolated. Here we report optically detected TSSE response in isolated FM stripes based on permalloy deposited on SiN substrate, upon the application of a thermal gradient. For these measurements we used the magneto-optic Kerr effect measured by an ultrasensitive Sagnac interferometer microscope that is immune to thermo-electrics artefacts. We found that the optical TSSE coefficient in the NiFe stripes geometry is about one order of magnitude smaller than that in the continuous NiFe film, which is due to the limited phonons path in the FM stripes along the thermal gradient direction. Our results further confirm the existence of TSSE response in conducting FM compounds.

Spin Wave Excitation, Detection, and Utilization in the Organic‐Based Magnet, V(TCNE)x (TCNE = Tetracyanoethylene)

“…Figure 1b displays a typical magnetic hysteresis loop of a thin ≈220 nm V(TCNE) x film measured by an ultrasensitive Sagnac magneto‐optic interferometer in transmission geometry with 1550 nm radiation at several temperatures. [ 30 ] The obtained magnetic coercivity is ≈0.5 mT at room temperature, consistent with previous studies utilizing other techniques. [ 11 ] Both the coercivity and magnetization significantly increase upon lowering the temperature.…”

“…The magneto‐optic Faraday rotation was measured by a modified fiber Sagnac interferometer operating at 1550 nm, which has a Faraday rotation angle resolution of ≈20 nrad. [ 30 ]…”

Magneto-Electroluminescence Study of Fringe Field in “Magnetic” Organic Light-Emitting Diodes

“…Magnetic hysteresis loops were measured at room temperature by Sagnac MOKE, which has much higher sensitivity than that of the conventional MOKE. 28 ■ ASSOCIATED CONTENT * S Supporting Information…”

Magneto-Optical Detection of Photoinduced Magnetism via Chirality-Induced Spin Selectivity in 2D Chiral Hybrid Organic–Inorganic Perovskites

“…Here, the magnetic field effects of chiral-HOIPs interfaced with NiFe contacts are studied using the magneto-optic Kerr effect (MOKE). This technique was chosen because of its proven sensitivity to small amounts of spin accumulation. , Figure outlines the general scheme of the experiment. A 405 nm laser photoexcites the chiral-HOIP, and a Sagnac interferometer is used to probe the change in out-of-plane magnetization using a 1550 nm laser beam that is incident on the sample’s surface along its normal direction.…”