Infrared optical properties of amorphous nickel-phosphorus alloys

• Published in: Physical review. B, Condensed matter Condensed matter, 1984-01, Vol.29 (12), p.6570-6575
• Main Authors: MCKNIGHT, S. W, IBRAHIM, A. K
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Infrared and raman spectra and scattering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics
• ISSN: 0163-1829; 1095-3795
• DOI: 10.1103/PhysRevB.29.6570

The room-temp. reflectivity in the spectral range 0.02-2.5 eV of electrodeposited Ni--P amorphous alloys containing 15-26 at.% phosphorus was measured. The data are well fit in the low-frequency region by the Drude model and the optical conductivities determined from the fit are in agreement with the published d.c. conductivities for these materials. Alloys with > 20 at.% P appear Drude-like to frequencies as high as 1.5 eV while those alloys with < 20 at.% P begin to deviate from free-electron behavior at frequencies approx 0.7 eV. Crystalline samples examined for comparison show structure at even lower frequencies. Values of the plasma frequency omega sub p and the inverse scattering time 1/ tau have been extracted for the amorphous alloys and both are found to decrease with increasing P content. Such a result is consistent with the gradual filling of the Ni d band, causing the density-of-states to decrease. This would imply that the d- and s-electron density-of-states enter additively into a single Drude term--possibly as a result of strong s-d scattering. 29 ref.--AA