Fig. 3 shows X-ray diffractograms from selected films. The film deposited at RT with − 25 V (Fig. 3(a)) produced diffraction peaks consistent with body-centred cubic (BCC) Fe and a low intensity {220} TiN peak, indicating the presence of both phases. The diffractograms from films deposited at biases of − 100 V, − 200 V, − 300 V and − 500 V (Fig. 3(b–e)) contain intense {220} TiN peaks and broad peaks in the region between 42° and 45° where {200} TiN and {110} BCC Fe peaks are expected. This indicates that the films deposited with applied bias contain more ordered TiN with a preferred crystallographic orientation. The film deposited at 500 °C produces intense peaks corresponding to BCC Fe but the {220} TiN peak is absent, indicating increased order in the BCC Fe phase and a change in the crystallography of the TiN phase. The low intensity peaks observed at ~ 57° are attributed to surface oxides.