Electric field dependence of microwave losses in strontium titanate II

474-476Electric field dependent microwave losses of an anharmonic pure strontium titanate ferroelectric crystal is calculated in its paraelectric phase from the Siverman Joseph Hamilton augmented with fourth order phnon-coordinates using double time Green's functions. The loss tangent consists of a contribution, which is quadratic in applied biasing plus a field independent contribution. The variation of tan δ with applied field is noticeable in the vicinity of the Curie temperature. In the higher temperature region, the electric field effect ceases and the increase in loss arises mainly due to higher order anharmonic terms. In SrTiO3, loss tangent increases with the increasing <span style="font-size:14.0pt;line-height:115%;font-family: " times="" new="" roman";mso-fareast-font-family:hiddenhorzocr;color:black;mso-ansi-language:="" en-in;mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">electric field.