MICROWAVE NONLINEAR DIELECTRIC MATERIALS.
Quarterly progress rept. no. 1, 15 Sep-14 Dec 63
RAYTHEON CO WALTHAM MA
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The dielectric nonlinearity of stannate-doped SrTiO3 and alumina-doped BST-50 were investigated in an attempt to duplicate the high nonlinearities observed in previous batches. No definite correlation has yet been made between doping and nonlinearity. The field-dependent loss tangent of BST-50 at room temperature has been measured. At this temperature the fielddependent component is about three times as large relative to the field-independent component compared to previous data at 151 C. The loss tangent and nonlinearity of KTaO3 have been measured at 4.2 K. Their surprisingly low values are discussed. An extension of the cavityperturbation technique used for measurements near the Curie point has been developed, so as to include the effects of sample losses. The theory applies to perturbations of arbitrary magnitude because it uses exact solutions. Author