2018/04/20 by Lukas Neumann, Neumann, Lukas, Markus Meinert +1
Engineering · Physics and Astronomy · Materials Science · #Magnetic Field Sensors Techniques #Magnetic properties of thin films #Magnetic Properties and Applications
paper · pdf · doi:10.48550/arxiv.1804.07577
Harmonic Hall voltage measurements are a wide-spread quantitative technique\nfor the measurement of spin-orbit induced effective fields in heavy-metal /\nferromagnet heterostructures. In the vicinity of the voltage pickup lines in\nthe Hall bar, the current is inhomogeneous, which leads to a hitherto not\nquantified reduction of the effective fields and derived quantities, such as\nthe spin Hall angle or the spin Hall conductivity. Here we present a thorough\nanalysis of the influence of the aspect ratio of the voltage pickup lines to\ncurrent channel widths on the apparent spin Hall angle. Experiments were\nperformed with Hall bars with a broad range of aspect ratios and a substantial\nreduction of the apparent spin Hall angle is already seen in Hall crosses with\nan aspect ratio of 1:1. Our experimental results are confirmed by\nfinite-element simulations of the current flow.\n