Piezoelectric tuning of exchange bias in aheterostructure
- 12 October 2010
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 82 (13)
- https://doi.org/10.1103/physrevb.82.134419
Abstract
Piezoelectrically controlled strain is used for electric tuning of exchange-bias fields. A generic exchange-bias Co/CoO bilayer is deposited on the surface of a ferroelectric and thus piezoelectric substrate which allows to apply electrically and thermally tunable stress in the adjacent ferromagnetic Co thin film. The stress-induced strain alters foremost the magnetic anisotropy of the Co film and by that the magnetization orientation at the Co/CoO interface modifying the exchange-bias field. This results in a pronounced electrically induced weakening of the exchange bias but also includes the possibility of tuning the exchange-bias field through a subtle sign change from regular negative to positive values. The electrically controlled crossover from negative to positive exchange bias is consistently observed at various temperatures in the rhombohedral phase of . This complex electric field dependence of the exchange-bias field is the result of the long-range nature of strain and interpreted through competition between ferromagnetic and antiferromagnetic exchange at the Co/CoO interface. Our data suggest competition between regular negative and positive exchange bias. Weakening of negative exchange bias originates from noncollinear alignment of the Co and CoO interface magnetizations. Positive exchange bias is activated when stress induces antiferromagnetic exchange through atomic displacements changing the exchange paths at the Co/CoO interface. DOI: http://dx.doi.org/10.1103/PhysRevB.82.134419 © 2010 The American Physical Society
Keywords
This publication has 88 references indexed in Scilit:
- Training effect in specular spin valvesPhysical Review B, 2008
- Interplay between exchange bias and uniaxial anisotropy in a ferromagnetic/antiferromagnetic exchange-coupled systemPhysical Review B, 2005
- Stable ultrahigh-density magneto-optical recordings using introduced linear defectsNature, 2001
- Exchange anisotropy — a reviewJournal of Magnetism and Magnetic Materials, 1999
- Memories are made of …Nature, 1999
- Exchange-biased magnetic tunnel junctions and application to nonvolatile magnetic random access memory (invited)Journal of Applied Physics, 1999
- Exchange biasJournal of Magnetism and Magnetic Materials, 1999
- MagnetoelectronicsScience, 1998
- Large exchange bias and its connection to interface structure in FeF2–Fe bilayersApplied Physics Letters, 1996
- Increased exchange anisotropy due to disorder at permalloy/CoO interfacesJournal of Applied Physics, 1995