Nitrogen ion implantation into ZrN thin films

Stoichiometric thin films of ZrN were implanted homogeneously in depth with N ions with multiple-energies at room temperature (RT) and at 380° C (HT) up to the concentration corresponding to x = 0.33 in ZrNi_{1 + x}. Structural properties, electrical resistivities and superconductivity were investigated with progressive implantations. X-ray diffraction experiments have revealed the preservation of the B1 structure throughout the whole implantation processes. Variation of the lattice parameter a₀ which is characteristic of B1 compounds at low implantation fluences and subsequent lattice expansion at high implantation fluences were observed with RT implantations, whereas a₀ showed gradual decreases at high fluences with HT implantations. Electrical resistivities increased with implantation fluences in both RT and HT implantations and showed poor conducting properties. The superconducting transition temperature T_c decreased below 1.3 K for RT implantation, while it remains at 33% of the initial value for HT implantations at the concentration with x = 0.33.