Search

Microwave dielectric investigations of SbS0.7Se0.3 I crystals were carried out over the frequency range 9 to 80 GHz. The main resonant dielectric dispersion caused by the soft mode occurs in the microwave range. On approaching the Curie point, the frequency of the microwave soft mode varies according to v2 r = A(T - T 0) with A = 1.1 × 1020 Hz2. K-1 and T 0 = 189 K in the symmetric phase, and with A = −3 × 1020Hz2. K−1 and T 0 = 193 K in the ferroelectric phase. The soft microwave mode does not belong to the set of normal modes. The phase transition is intermediate between the pure displacive and order-disorder types.