Dependence of dielectric constant and loss tangent on electric field in antiferroelectric squaric acid crystal

The double-time thermal Green function method with the symmetric and antisymmetric decoupling scheme and modified pseudospin model proposed by Li and Qin for squaric acid have been used in present study to discuss the effect of electric field on some dielectric properties. Expressions for shift, width, soft mode frequency, dielectric constant, loss and transition temperature have been evaluated. By fitting model values of physical quantities in the theoretical expressions thermal dependence of antiferroelectric mode frequency, dielectric constant and loss have been calculated in presence of electric field in the vicinity of transition temperature. Theoretical results are similar to other antiferroelectric crystals.