Searching for room temperature ferromagnetism in transition metal implanted ZnO and GaN

Significant progress in the field of wide-gap dilute magnetic semiconductors (DMS) depends on the discovery of a material system which not only shows high-temperature ferromagnetism but is also simple to prepare and thus easy to reproduce. In this context, ion implantation is an attractive doping method, being both relatively simple and highly reproducible. Here, we report on the search for high-temperature ferromagnetism in ZnO and GaN implanted with Mn, Fe, and Co, prepared under a wide range of implantation and post-processing conditions. We focused on the low concentration regime (similar to 0.3 - 4%) in order to avoid phase segregation and applied strict experimental procedures to avoid ferromagnetic contamination. Despite the wide range of materials, implantation and post-processing conditions, none of the DMS systems showed room-temperature ferromagnetism. These results support the view that dilute transition-metal moments do not order ferromagnetically in ZnO and GaN. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4774102]