Critical phenomena in antiferroelectrics

An equation of state for an antiferroelectric is proposed, which couples the field strength, temperature, and polarization, and has isotherms that display double hysteresis loops and a critical point. On the phase diagram of field versus temperature two critical points, symmetrically placed with respect to the temperature axis, are observed. The presence of a critical point on the temperature-polarization and temperature-entropy diagrams is also shown.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 27–31, September, 1972.The author wishes to thank Prof. Semenchenko for his interest in this work and valuable comments.