Effect of pressure on the resistivity of spinel ferrite

The far-infrared spectra of six mixed ferrites (CdxCo1−x+tTitFe2−2tO4; x=0.2, 0.00⩽t⩽0.25) in the range 200-1000 cm−1 are reported. Two strong high-frequency bands ν1 and ν2 are observed. The first one ν1 is assigned to the tetrahedral and the second ν2 is assigned to the octahedral site. A small kink ν3 around near ν2 is observed and its intensity increases with divalent octahedral metal ion concentration. Seebeck coefficient measurements showed that the substitution of tetravalent ion Ti4+ does not change the polarity of the Seebeck coefficient from p- to n-type. The activation energy and the carrier mobility μ were also calculated. The effect of mechanical pressure on the dc resistivity was investigated.