The Dielectric Properties of the Rutile Form of TiO2

Abstract

Three specimens of rutile were prepared and the dielectric properties studied over a range of frequency and temperature. A dielectric constant of approximately 100 was found which remained substantially constant through the highest radiofrequencies, falling off only in the infra‐red region. The dielectric losses are low, particularly at the higher frequencies. The dielectric constant decreases with increasing temperature, having an average temperature coefficient of −8.2×10⁻⁴/°C. An exponential relationship between conductivity and the reciprocal of the absolute temperature holds for rutile in the higher temperature region. Mixtures of rutile powder with other dielectric materials obey a logarithmic mixture formula. Two mechanisms which have been proposed to explain the high dielectric constant of rutile are discussed. A simple mechanism based on the Clausius‐Mosotti equation is described.