Optical conductivity of Ni1 - xPt x alloys (0<x<0.25) from 0.76 to 6.6 eV.

Using spectroscopic ellipsometry and Drude-Lorentz oscillator fitting, we determinedthe dielectric function and optical conductivity versus photon energy from 0.76 to6.6 eV of 10 nm thick Ni1 ? xPtx alloy (0<x<0.25) films deposited on thick thermaloxides. We find absorption peaks near 1.6 and 5.0 eV due to interband opticaltransitions. There is a significant broadening of the UV peak with increasing Ptcontent, since the bandwidth of the 3d electrons in Ni is smaller than that of the 5dbands in Pt. Our experimental observation is consistent with ab initio calculationsof the density of states for Ni, Pt, and the Ni3Pt compound. Annealing the metals at500?Cfor 30 s increases the optical conductivity. [ABSTRACT FROM AUTHOR]