Abstract
The integration of ferroelectric polymer gates on a Mn-doped GaAs magnetic channel provides a promising route for the persistent field-effect control of magnetic properties in high-quality diluted magnetic semiconductors (DMSs) that are otherwise incompatible with traditional oxide ferroelectrics. That control demands the thinnest possible DMS layers, for which to date the Curie temperature () is severely depressed. Here we show that reducing the channel thickness from 7 to 3–4 nm by etching, followed by a brief 135 °C anneal, does not degrade the (∼70 K) of the 7-nm film. The channel thinning results in a dramatic threefold increase of the shift controlled by the ferroelectric polarization reversal. Furthermore, we obtain the same exponent for all channels with different thicknesses, regardless of the technique used for determination. These results suggest that the ferromagnetic coupling in an ultrathin 3-nm channel is far from the two-dimensional limit and shows a rather bulklike behavior, similar to well-established 7-nm films.
- Received 5 January 2011
DOI:https://doi.org/10.1103/PhysRevB.83.115203
©2011 American Physical Society