Date of Award
Doctor of Philosophy
Measurements of the optical absorptivity of 0.75 atomic % Ni in Ag are reported. The reference film, Ag, and the sample film, Ag(Ni), were rf sputtered onto sapphire substrates. Spectra were obtained using differential AC calorimetry over the energy range 0.3 to 3.3 eV. The spectra show one peak near 3 eV and one incomplete structure at the low energy end of the measurements. The 3 eV peak is attributed to differences in grain structure between the sample and reference films;In contrast to the results and assignments of Koike, Yamaguchi and Hanyu 1 , no structure at 1.8 eV is observed. Their assignment of the 1.8 eV peak as a virtual bound state peak is questioned. These data agree with their observation of structure near 0.5 eV. Their resis- tivity and thermoelectric power data are consistent with the assign- ment of a virtual bound state near 0.5 eV. A recent calculation of the electronic structure of Ag(Ni) and Cu(Ni) by Singh, Raj and Prakash 2 suggests that the VBS structure of Ag(Ni) is close in energy to that observed in Cu(Ni). The absence of 1.8 eV structure in these data, the agreement on the presence of low energy structure, the consistency of a low energy virtual bound state peak with measurements of other quantities, the systematic of virtual bound state structures of Pd and Ni in Cu, Ag and Au and the calculations of electronic structure of Ag(Ni) suggest that the low energy structure may be the virtual bound state for Ag(Ni);Measurements of absorptivity which extend farther into the infrared are required to conform this assignment; References 1 H. Koike, S. Yamaguchi and T. Hanyu, J. Phys. Soc. Jpn. 38, 1370 (1975). 2 J. Singh, S. D. Raj and S. Prakash, Nuovo Cimento D 4, 469 (1984).
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
James L. Wolf
Wolf, James L., "Optical properties of dilute Ag(Ni) alloys " (1985). Retrospective Theses and Dissertations. 12120.