Domain structure and magnetization reversal ofantiferromagnetically coupled perpendicular anisotropy films
We describe experimental and theoretical investigations ofthe magnetic domain formation and the field reversal behavior inantiferromagnetically coupled perpendicular anisotropy multilayers thatmimic A-type antiferromagnet (AF) structures. The samples are sputterdeposited Co/Pt multilayers with perpendicular anisotropy that areperiodically interleaved with Ru to mediate an antiferromagneticinterlayer exchange. This structure allows precise tuning of thedifferent magnetic energy terms involved. Using various magnetometry andmagnetic imaging techniques as well as resonant soft X-ray scattering weprovide a comprehensive study of the remanent and demagnetizedconfigurations as well as the corresponding reversal mechanisms. We findthat adding AF exchange to perpendicular anisotropy system alters thetypical energy balance that controls magnetic stripe domain formation,thus resulting in two competing reversal modes for the composite system.In the AF-exchange dominated regime the magnetization isferromagnetically ordered within the film plane with the magnetization ofadjacent layers anti-parallel thus minimizing the interlayer AF exchangeenergy. In the dipolar dominated regime the magnetization pattern formsferromagnetic (FM) stripe domains where adjacent layers are verticallycorrelated, but laterally anti-correlated thus minimizing the dipolarenergy at the expense of the AF interlayer coupling. By tuning the layerthickness or applying a magnetic field, we observed the co-existence ofAF domains and FM stripe domains. We find that a FM phase exists at AFdomain boundaries, causing complex mesoscopic domain patterns withsurprising reversibility during minor loop field cycling.
- Research Organization:
- COLLABORATION - Hitachi Global StorageTechnologies
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 929667
- Report Number(s):
- LBNL-63341; JMMMDC; R&D Project: 504103; TRN: US200812%%740
- Journal Information:
- Journal of Magnetism and Magnetic Materials, Vol. 319, Issue 1-2; Related Information: Journal Publication Date: online05/08/2007; ISSN 0304-8853
- Country of Publication:
- United States
- Language:
- English
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