A method for obtaining, with high selectivity as compared to a conventional method of mixing reaction substrates and thereafter reacting the mixture under heating, a facial isomer of tris-orthometallated iridium that is suitably used particularly as an organic electroluminescence device material, among complexes of tris-orthometallated iridium. The first system comprises the first UE and the first RNN serving the first UE. These low barrier height insulating materials allow for the formation of a magnetic tunnel junction with a relatively thick barrier while maintaining a low resistance that is suitable, for example, in magnetoresistance read head applications.