Observation and implications of magnetic domains in lateral spin valves

Co/Cu/Co lateral spin valves (LSV), with Co being the topmost layer, are in situ prepared and measured under ultrahigh vacuum conditions. The clean process yields a non-local spin signal of 0.9 mΩ . Scanning electron microscopy with polarization analysis (SEMPA) reveals domain structures in both magnetic electrodes that depend on the LSV dimensions. The spin signal correlates to SEMPA images as well as the anisotropic magnetoresistance of both Co magnets, revealing a strong impact of multi-domain states on the spin signal.

Figure:(a) SEMPA images of the domain structure of (a) the LSV depicted in Fig. 1 and (b) a test structure fabricated without substrate roughening due to FIB milling

Figure: AMR measurements of ferromagnet (FM) 1 and FM2 (vertically offset for clarity) and spin current signal RS(H). (dotted and solid lines corresponds to two measurement runs) of a LSV with 270-nm-wide FMs. Arrows indicate the field sweep direction. Framed pairs of arrows represent the relative alignment of the magnetizations of FM1 and FM2 at the respective FM/ NM interfaces..

J. Mennig, F. Matthes, D. E. Bürgler, and C. M. Schneider
Observation and implications of magnetic domains in lateral spin valves
Journal of Applied Physics 111 , 07C504 (2012)