Magneto-transport behaviors of (Ga,Mn)as based nano-structures and devices

Abstract

As a widely accepted magnetic semiconductor with an intrinsic ferromagnetism, (Ga,Mn)As has attracted much attention in the past decades, and many kinds of extraordinary spintronic functionalities have been realized based on this kind of material. However, increasing the Curie temperature (TC) of (Ga,Mn)As above room temperature is a necessity for potential applications. In this chapter, an overview of several ways used recently to increase TC will be provided. Firstly, we will show that TC of (Ga,Mn)As can be increased to 190 K by heavy Mn doping employing low-temperature molecular-beam epitaxy and post-growth annealing. Then, we will demonstrate that TC as high as 200 K can be achieved in (Ga,Mn)As by combining a nano-patterning technique with high Mn doping and low-temperature annealing. After that, we will present the strong carrier localization effect existing in heavily Mn-doped (Ga,Mn)As films. Finally, we will mention an unconventional way to fabricate (Ga,Mn)As-based magnetic tunneling junction, in which a highest tunneling magnetoresistance ratio of 101 % could be achieved at 2 K.