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Dependence of the anisotropic magnetoresistance on aspect ratio in cobalt films.
M. Tondra, B. H. Miller, E. D. Dahlberg
J. Appl. Phys. 75 p. 6567 (1994).
Abstract: Summary form only given. High quality measurements of the anisotropic magnetoresistance, defined as the difference in the resistivities when the saturated sample magnetization is parallel and perpendicular to the current, are performing using four terminal measurements. What is occasionally not considered in these measurements is the geometry of the sample and contacts. This work reports how the anisotropic magnetoresistance (AMR), measured with four in-line point contacts attached to thin film specimens, is affected by the geometry of the films. Cobalt samples were lithographically narrowed in 2 mm steps from 10 mm*10 mm to 2 mm*l0 mm. For each of the five sizes, the AMR and resistivity were measured using the four-probe-in-line technique with 3 mm from one contact to the next. The results show that the measured AMR increases by a factor of 2 from the widest to narrowest size. This width dependence of the AMR arises from spreading of the current between the voltage contacts. In order to make an accurate assessment of the AMR, the current across the entire width of the sample must be parallel to the line joining the voltage contacts. Similar work has been performed by A. Iwaide et al., and published in J. Magn. Sec. Jpn. 16, 197 (1992). The results reported in this abstract are in agreement with those in the above-mentioned paper. (0 References).
last modified:
10.Jun.2002
by Thomas Gredig