Magnetic and spin-dependent transport properties of reactive sputtered epitaxial Ti1−xCrxN films

Abstract Reactive-sputtered epitaxial Ti 1− x Cr x N 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 ρ 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 ρ 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 ρ xy A ∝ ρ xx 2 , which is from the side-jump mechanism.