SbSI Crystals Research Articles

Preparation and some physical properties of SbSI and SbSeI films: N I Dovgoshey et al, Semiconductor Electronics, Collect, Uzhorod 1971, 1971, 66–70 ( in Russian)

Single crystals of SbSI have been grown from SbI3 flux by directional cooling through a temperature gradient. The morphology of the crystals is found to be dependent on the growth parameters: (1) composition of the mixture of Sb2S3 and SbI3 flux; (ii) temperature gradient, and (iii) rate of lowering (or cooling). Single crystals highly oriented parallel to the ferroelectric c-axis can be produced by this method in the form of fine parallel needles, thin parallel plates and larger size plates. Characterization information and a brief description of some applications for the single and polycrystal forms produced are given.

Anomalous absorption and velocity dispersion of ultrasonic waves in SbSI crystals (measurements near the phase transition in the frequency range 10–30MHz): Samulionis, V.I., and Kunigelis, V.F. Soviet Physics-Solid State, Vol 11, No 3 (September 1969) (2211)

Anomalous absorption and velocity dispersion of ultrasonic waves in SbSI crystals (measurements near the phase transition in the frequency range 10–30MHz): Samulionis, V.I., and Kunigelis, V.F. Soviet Physics-Solid State, Vol 11, No 3 (September 1969) (2211)

The growth of large SbSI crystals: Control of needle morphology

SbSI crystals have been grown by many techniques, all of which yield long thin needles because of an inherent growth rate anisotropy greater than 50:1. A modified flux technique using excess SbI 3 as the solvent was devised to circumvent this difficulty. Nucleation is initiated in a large temperature gradient in a narrow extension of the growth vessel. The main part of the growth vessel is essentially isothermal. As the temperature is lowered a few crystals grow from the nucleation region into the main part of the growth vessel. In the absence of further nucleation these crystals are forced to grow in thickness, yielding crystals up to 1 cm in diameter.

On the preparation, properties, and possible ferroelectricity in SbI 5

Two methods have been described for the growth of single crystals of SbSI. This paper reports that one method produces not SbSI, but SbI 5. The stoichiometry was checked by chemical analysis. The interplanar spacing obtained by X-ray diffraction is in agreement with a close-packed structure similar to that reported for SbCl 5. Optical studies reveal a domain structure. Application of electric fields produces changes in extinction area. This effect may be evidence for ferroelectric domain wall motion, but electrostrictive effects could not be ruled out.

Electrical Properties of the Hot-pressed SbSI Polycrystals

SbSI is a ferroelectric material with the c-axis as ferroelectric axis and the most strongly piezoelectric material known. The permittivity of SbSI single crystal of the c-direction is about 25000 whereas that of the a-direction is 25. Till now, due to the difficulties in obtaining large crystal, it is very hard to use this material for practical applications. Specimens used in piezoelectric measurement reported by RCA group consisted of thin discs cut from bundles of SbSI needles embedded in Araldite.SbSI single crystal tends to grow in form of thin needles along the c-axis. In this report, the hot-pressing technique was applied to the powder of SbSI crystals in order to obtain the hard polycrystalline ingot having the oriented c-axis and systematic experiments were carried out on the effects of the hot-pressing temperature (Tm), the pressure (Ph) and the time (tp) influencing upon the orientation of the c-axis in the hot-pressed specimens.The results obtained are summarized as follows.(1) When Ph was applied to the z-direction of the press mould, the c-axis of SbSI microcrystals were oriented in the x-y plane of the press mould. In this case, the permittivity of the x-direction (ex) is 1400 at the Curie point whereas that of the z-direction (ez) is 160.(2) When the pre-forming pressure to the y-direction and the hot-pressing pressure to the z-direction were applied, the c-axis were oriented to the x-direction of the pressed specimens. In this case, the permittivity of x, y, and z-directions at the Curie point are 3000, 1000, and 240 respectively.(3) The orientation of the c-axis in the hot-pressed specimens was also ascertained by the observation of the etched surface by mean of a microscope.(4) The piezoelectric constants such as k33, s33E, s33D, d33, fR⋅t were measured for the hot-pressed specimens prepared under a condition of Tm=370°C, Ph=250kg/cm2, and tp=1hr. This specimens showed an electromechanical coupling coefficient k33 of 35%.(5) The Curie temperature of the hot-pressed SbSI of 30°C is higher by 10°C than that of the SbSI single crystal If the phase transition of SbSI is order-disorder type, it may be considered that the rise of the Curie point by the hot-pressing is the effect of the residual strain generated while hot-pressing.

Photo-Induced Microwave Response in SbSI Crystals

Photo-Induced Microwave Response in SbSI Crystals

Temperature Dependence of the Refractive Index _nc in SbSI Through the Ferroelectric–Paraelectric Transition

Single crystals of SbSI have shown large changes in refractive index through the paraelectric-ferroelectric transition for light polarized parallel to the ferroelectric c axis. Near the absorption edge, the observed change is discontinuous. Large changes in refractive index can also be induced by pulsed electric fields along the c axis. The extreme anisotropy of SbSI is indicated by the large partial birefringences observed in the paraelectric phase.

Anomalous Pyroelectric Properties of SbSI Single Crystals

The pyroelectric current in single crystals of SbSI was measured continuously with a d.c. amplifier and a recorder in the temperature range from -170°C to +40°C. The spontaneous polarization was estimated from these measurements. The pyroelectric current in a virgin crystal (free from previous poling treatment) showed several peaks near the Curie point. Optical observation of the crystal carried out simultaneously with the recording of the pyroelectric current revealed that these anomalous peaks corresponded fairly well to the movements of the ferroelectric-paraelectric phase boundaries. The peaks have a tendency to be replaced by a large, main peak when poled with a high d.c. field, and the main peak is again forked into several by irradiation with white light.