Electrical Transport in Semiconducting (LaMn1−xTix)1−γO3(x≤0.05)

✍ Scribed by W.H. Jung; H. Nakatsugawa; E. Iguchi

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 302 KB
• Volume: 133
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7511

✦ Synopsis

Electrical transport properties in the ceramic specimens of (LaMn 1؊x Ti x ) 1؊ O 3 system (x40.05) have been investigated as a function of temperature by the complex-plane impedance analyses, dielectric properties, four-probe DC conductivities, and Seebeck coefficients. The complex-plane impedance analysis distinguishes the bulk conduction from the conduction across the grain boundaries. The bulk conduction contains two thermally activated processes separated at the Ne´el temperature (T N ).

A dielectric relaxation appears in a loss tangent and electric modulus below T N . The activation energy required for the relaxation is nearly equal to that for the conduction at T < T N . The electrical transport below T N is explained self-consistently in terms of a hopping process of small polarons of holes, which are formed by a superexchange interaction and are more deeply localized by the assistance of the Jahn-Teller effect. A correlation between the bulk conduction at T > T N and the hopping process of small polarons of holes is also discussed.