ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Co/Au(111) is a model system for magnetoresistance (MR) studies due to abrupt interfaces without intermixing between Co and Au and perpendicular magnetization of Co films for Co thickness below nine atomic monolayers (AL). The high quality of Co/Au(111) multilayers is revealed by highly contrasted MR oscillations versus Au spacer thickness. We report here a detailed study of the effect of cobalt thickness done to 0.2 AL on the MR of various Au/Co structures. Experiments were performed on single Co layer sandwiched between two Au(111) films, Au/Co/Au, and on double Co films, Au/Co/Au/Co/Au, in the T range 1.5–300 K and in magnetic fields up to 10 T. For the sandwiches, two series were studied, each including eight samples grown in UHV in a single run, with Co thicknesses tCo from 0.2 to 1.6 and from 1.4 to 4 AL. The MR in the perpendicular and transverse configurations show that the easy magnetization axis is perpendicular to the films, even for low tCo. The MR value increases with tCo to the high value of 5% at low temperatures for a noncontinuous Co film and decreases afterwards, clearly evidencing the transition from islandlike to continuous-like character of the Co film. In the islandlike regime, the magnetic domain size is limited by the island size and is thus smaller than in the continuous Co films, leading to higher MR values. In the double Au/Co/Au/Co/Au samples, different Au spacer thicknesses were chosen in order to ensure either FM or AFM coupling between the magnetic layers, and tCo was varied up to 10 AL. We did not observe coupling oscillations versus tCo. Moreover, the lack of any significant variations of the MR value shows that the electronic mean free path in Co is larger than 10 AL at any T.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.358190
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