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Nonlinear Dielectric Constants in Barium Titanate

1973; Physical Society of Japan; Volume: 34; Issue: 2 Linguagem: Inglês

10.1143/jpsj.34.418

1347-4073

Takashi Matsuda, Ryuji Abe,

Geophysics and Sensor Technology

An apparatus for detecting small second and third harmonics due to the dielectric nonlinearity is devised. A reactance filter network is used to obtain pure sine wave voltage and high detection sensitivity. The higher harmonic level applied to the crystal is suppressed to the order of 5×10 -7 times below the fundamental voltage. This apparatus is used for measuring the nonlinear dielectric constants of BaTiO 3 single crystals above and below the Curie point (120°C). The experimental results show that the coefficient of the P 4 term in the Devonshire's equation increases gradually with increasing temperature, which is against the previous result reported by Drougard et al.