l'lic full-faccd crystals of triglycinc sulphate (TGS) and deuterated hornologs substituted by I4-a1aniiio (LATGS arid LADTGS, resp.) wcrc grown from growth solutions with various concentratloris of the sribstituerit. The distribution of L, alanirie (L,al) in various growth pyramids of crystals was measured by the electrical switching method. Tho stability of domain structure of doped crystals was studied by the liquid crystal method.

h drscriptioii of the various orientations of microstructure and large single crystals of triglycine sulphate (TGS) is reviewed. A difference of the orielitation of TGS in polydornain statc anti in two possible singledomain states is discussed. The conclusions arc applied t o TGS crystals doped with L, alariirie or U, alanine.

No abstract

A substantial increase of the ferroelectric phase transition temperature with hydrostatic pressure was observed for lithium thallium tartrate monohydrate single crystals. The temperature dependence of the permittivity ε a shows an unusual shape exhibiting a broad plateau in ε a (T ) below T c . It follows from our hysteresis loop measurements that the domain wall motion freezes approximately 5-15 K (this value is pressure dependent) below T c and causes the drop in ε a (T ). The temperature and pressure dependence of the soft-mode frequency was measured by far-infrared as well as Raman spectroscopy at 10-300 K and 0.1-440 MPa. The soft mode softens only incompletely because of its strong coupling with a transverse acoustic mode.

The single crystals of triglycine sulfate doped with bivalent and tetravalent Pt-ions and with L-alanine (LADTGS/Pt(II) and LATGS/Pt(IV)) were grown in the ferroelectric phase from low temperature solutions. Using stick seeds the full-shaped crystals with many growth pyramids have been prepared. The growth rate along the axis c of the doped crystals is much higher than in an undoped one. Morphology, domain structure and P-E hysteresis loops have been investigated. The effect of the dopant on the growth velocity is explained on the basis of catalytic action of supposed platinum complexes. The first series of the pyroelectric detectors have been prepared from these materials and their fundamental parameters are presented.