Abstract
Reactive-sputtered epitaxial Ti1-xCrxN films are ferromagnetic in the range of 0.17 <= x <= 0.51 due to the Cr-N-Cr double-exchange interaction below the Curie temperature (T-C). The T-C first increases, then decreases as x increases, and a maximum of 120 K appears at x = 0.47. All of the films are metallic with a transition near T-C. A resistivity minimum rho(min) is observed below 60 K in the films with 0.10 <= x <= 0.51 due to the effects of the weak localization and electron-electron interaction. The negative magnetoresistance (MR) is caused by the double-exchange interaction below T-C and the weak localization can also contribute to MR below T-min where rho(min) appears. The x-dependent electron carrier densities reveal that the ferromagnetism is not from the carrier-mediated mechanism. The anomalous Hall resistivity follows the relation of rho(A)(xy) proportional to rho(2)(xx), which is from the side-jump mechanism. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.