Hybrid devices with high-density nanometallic and nanomagnet dots embedded in the semiconductor

A homogeneous metallic dot array embedded in an InAs two-dimensional electron system has been fabricated with a dot density as high as 10(8) cm(-2). This hybrid device consists of three different areas: one is an antidot array, in another permalloy (Py) is embedded in the holes, and in the third area Ti/Au is filled into the semiconductor. This design enables to distinguish on the same sample, in situ, the effects of metallic and ferromagnetic behaviors of the embedded nanostructures. A hysteretic magnetoresistance effect and a memory effect in the Py embedded area has been observed at 4.2 K while the Ti/Au area does not show these effects. Considering that there are more than 1x10(6) nanomagnet dots embedded in the device, the magnetoresistance of 0.25% for an in-plane magnetic field demonstrates the large area homogeneity of the embedded nanodots. (c) 2006 American Institute of Physics.