Date of Award

2013-01-01

Degree Name

Master of Science

Department

Mechanical Engineering

Advisor(s)

Chintalapalle V. Ramana

Abstract

The effect of hafnium ion (Hf4+) incorporation in cobalt ferrite (CFO) was studied. Samples of Hf substituted CFO ceramic (CoFe2-xHfxO4), were synthesized in the laboratory with hafnium concentrations ranging from x=0.000 to x=0.200. X-ray diffraction scans show that the Hafnium CFO crystalizes in the inverse spinel phase. Inclusion of hafnium causes lattice expansion, increasing the lattice parameter from 8.374 í? for pure CoFe2O4 to 8.391 í? for the highest concentration of hafnium tested (x=0.020). The dielectric properties of CFO are greatly enhanced by inclusion of hafnium. The enhancement is due to the distortion on the lattice from the larger Hf-ions substituting the smaller Fe-ions. Frequency variation of the dielectric properties is well modeled by the modified Debye function, which takes into account multiple ions contributing to relaxation.

Language

en

Provenance

Received from ProQuest

File Size

43 pages

File Format

application/pdf

Rights Holder

Stephen Josiah Wells

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