Abstract
We study experimentally the effect of electric field on the magnetization of Co/AlO granular multilayers. We observe two distinct regimes: (a) low-field regime when the net magnetization of the system changes in a reversible way with the applied electric field and (b) high-field regime when the magnetization decreases irreversibly. The former is attributed to the changes in the relative 3orbital occupation of the minority and majority bands in the Co granules. A theoretical model has been developed to explain the electric-field-induced changes in the band structure of the granular system and hence the magnetic moment. The latter result may be understood assuming the electric field induces oxygen migration from AlO to the Co granules, since an increase in oxidation state of the Co granules is shown, through ab initio calculations, to give rise to a reduced magnetization of the system.
- Received 19 June 2012
DOI:https://doi.org/10.1103/PhysRevB.87.014425
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