Switching of sub-micrometer sized, antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers

摘要

This work reports on the magnetic reversal of sub-micrometer sized elementsconsisting of an CoFeB/Ru/CoFeB artificial ferrimagnet (AFi). The elements werepatterned into ellipses having a width of approximately 250 to 270nm and avarying aspect ratio between 1.3 and 8. The coercivity was found to decreasewith an increasing imbalance of the magnetic moment of the twoantiferromagnetically coupled layers and is therefore strongly affected by anincrease of effective anisotropy due to the antiferromagnetic coupling of thetwo layers. With respect to a single layer of amorphous CoFeB, patterned incomparable elements, the AFi has an increased coercivity. Switching asteroidscomparable to single layers were only observed for samples with a high netmoment.