Galvanomagnetic properties of GaMnAs layers obtained by ion implantation: the role of Mn$^+$ ion energy

The galvanomagnetic properties of GaMnAs layers obtained by implantation of Mn+ ions and subsequent pulsed laser annealing were studied. The optimal value of the KrF excimer laser pulse energy density ($\sim$ 300 mJ/cm$^2$) for the electrical activation of implanted Mn atoms has been established. It has been shown that layers formed with a dose of (3–5) $\cdot$ 10$^{16}$ cm$^{-2}$ are ferromagnetic after laser annealing, and the implantation energy has virtually no effect on the Curie temperature. It was found that the hysteresis loop width in the anomalous Hall effect strongly depends on the implantation energy: coercive field decreases with decreasing ion energy from 200 to 40 keV.