We present results of an experimental study on the effect of the inclusion of ferroelectric thiourea particles in paraelectric amorphous KBr on the ferroelectric phase transition. The phase transition as a function of temperature has been observed with optical second-harmonic generation (SHG) of infrared light. The Curie temperature Tc shows a minimum as a function of the volume fraction x of thiourea in the composites at x = 0.4. We describe the experimentally observed density dependence of the Curie temperature in a phenomenological mean-field model.

J. Appl. Phys.

Kroon, M., Kroon, R., Sprik, R., & Lagendijk, A. (1995). Ferroelectric phase transition in thiourea:KBr composites studied with optical second-harmonic generation. J. Appl. Phys., 77, 806–810.