Epitaxy of Fe on GaAs by the MBE technique has a long tradition in magnetism research. This paper deals with the growth of epitaxial Fe-GaN-Fe trilayer structures whose intriguing magnetic properties were exploited for the evaluation of GaN as a spin-dependent tunneling barrier. The trilayers were grown on semi-insulating (0 0 1) GaAs using an ultra-high vacuum deposition chamber equipped with electron cyclotron resonance (ECR) microwave plasma nitrogen source.