Correlation between the signs of the magnetoresistance and of the interlayer coupling in MnGa/(Mn,Ga,As)/MnGa trilayers

A correlation is found between the sign of the magnetoresistance ΔR=(RP−RAP) and the sign of the interlayer coupling in MnGa/(Mn,Ga,As)/MnGa trilayers (subscript P, AP=parallel, antiparallel magnetic alignment of both MnGa layers). Ferromagnetic coupling results in ΔR<0, antiferromagnetic coupling results in ΔR>0. This correlation has not been observed before and can not be explained by the usual model for giant magnetoresistance in magnetic multilayers.