Baric dependence of the fundamental absorption edge in the region of phase transitions of Sn2P2S6-type intrinsic ferroelectrics

The energy position of the fundamental absorption edge in the neighborhood of phase transitions in Sn₂P₂S₆ and (Pb_0.1Sn_0.9)₂P₂S₆ ferroelectric crystals is studied as a function of the temperature and baric dependence on the basis of direct measurements of the isoabsorption relations. Thep, T phase diagram of Sn₂P₂S₆ crystals is constructed. the temperature-dependent variation of the band gap in those crystals is due mainly to electron-phonon interaction. Uzhgorod State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 82–85, August, 1997.     

Spin-glass, antiferromagnetism and kondo behavior in Ce2Au1−x Co x Si3 alloys

Recently, the solid solution Ce₂Au_{1− x Co} xSi₃ has been shown to exhibit many magnetic anomalies associated with the competition between magnetic ordering and the Kondo effect. Here we report high pressure electrical resistivity of Ce₂AuSi₃, ac susceptibility (X) and magnetoresistance of various alloys of this solid solution in order to gain better knowledge of the magnetism of these alloys. High pressure resistivity behavior is consistent with the proposal that Ce₂AuSi₃ lies at the left-hand side of the maximum in Doniach’s magnetic phase diagram. The ac X data reveal that there are in fact two magnetic transitions, one at 2 K and the other at 3 K for this compound, both of which are spin-glass-like. However, as the Co concentration is increased, antiferromagnetism is stabilized for intermediate compositions before attaining non-magnetism for the Co end member.     

The growth of a single crystal of Sr3CuIrO6 and its magnetic behavior compared to polycrystals

We have grown single crystals of the psuedo-one-dimensional compound Sr₃CuIrO₆, a K₄CdCl₆-derived monoclinic structure with Cu-Ir chains along the [101] direction. We present the ac and dc magnetization behavior of the single crystals in comparison with that of the polycrystalline form reported earlier. There is a distinct evidence for at least two magnetic transitions, at 5 K (T ₁) and 19 K (T ₂), with different relative magnitudes in the single and polycrystals. The low temperature magnetic relaxation behavior of both the forms is found to be widely different, exhibiting unexpected time dependence.     

Phase transitions in the ferroelectrics (Sn1−x In(2/3)x )2P2S6 at high pressures

New ferroelectric solid solutions (Sn_1−x In_(2/3)x )₂P₂S₆ were investigated at high hydrostatic pressures. The range in which the incommensurate structure exists was determined. A dynamic shift of the incommensurate-ferroelectric phase transition temperature with increasing rate of change of temperature and the appearance of “reverse hysteresis” were observed. The characteristic features in the appearance of the latter effect in these crystals are investigated. Fiz. Tverd. Telsa (St. Petersburg) 41, 1276–1278 (July 1999)     

Influence of isomorphous substitution and external hydrostatic pressure on the fundamental light-absorption edge in Sn(Pb)2P2S(Se)6 crystals

The influence of isomorphous substitution and high hydrostatic pressure on the behavior of the fundamental absorption edge (AE) inSn(Pb) ₂ P ₂ S(Se) ₆ ferroelectric crystals is studied. It is shown that the AE in these crystals is caused by an electron-phonon interaction, and oscillation frequencies of interacting phonons correspond to oscillations of the[P ₂ S(Se) ₆]⁴⁻ anion sublattice. Baric and concentration changes of the Uhrbach rule parameters are analyzed. Uzhgorod State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 23–28, September, 1999.     

Dynamic shift of the phase-transition temperature in (Sn1−x In(2/3)x)2P2S6 crystals with incommensurate phase

The dielectric properties of ferroelectric (Sn_1?x In_(2/3)x )₂P₂S₆ crystals were studied in the region of incommensurate phase transitions occurring upon fast cooling and heating (0.2–11 K/min). The dynamic phase-transition shift observed in these materials was examined.     

A decade of yeast surface display technology: where are we now?

Yeast surface display has become an increasingly popular tool for protein engineering and library screening applications. Recent advances have greatly expanded the capability of yeast surface display, and are highlighted by cell-based selections, epitope mapping, cDNA library screening, and cell adhesion engineering. In this review, we discuss the state-of-the-art yeast display methodologies and the rapidly expanding set of applications afforded by this technology.