Piezoelectric Properties of TlIn1−x Nd x Se2 Crystals

The piezoelectric properties of TlIn_1–x Nd _x Se₂ crystals (0 x 0.05) have been investigated. It has been found that these crystals possess high coefficients of tensosensitivity which change on partial substitution of the indium atoms by neodymiun atoms and strongly depend on the intensity of the spectral composition of optical illumination.     

Growth and Properties of V-Doped CdxHg1 – xTe Crystals

Cd _x Hg_{1 – x} TeV (x= 0.9–0.95) crystals were prepared by two versions of Bridgman growth, and their optical homogeneity and transport properties were studied. The electrical resistivity of the crystals was 10⁴to 10⁸ m. From the temperature dependences of the Hall coefficient, the activation energy of the vanadium level in Cd _x Hg_{1 – x} TeV was determined to be 0.73–0.82 eV.     

Growth and Properties of KTi1 – xSnxOPO4Crystals

Single crystals of KTi_{1 – x} Sn _x OPO₄solid solutions and KSnOPO₄were grown from off-stoichiometric flux, and their structure and physical properties were studied. The replacement of Ti by Sn was found to increase the unit-cell parameters, shift the ferroelectric transition to lower temperatures, and decrease the nonlinear optical susceptibility. Near t _C, some of the crystals exhibit a jump in electrical conductivity, typical of superionics.     

Preparation and Properties of CuCr1 – x V x Se2 Solid Solutions

The phase relations in the CuSe–(1 – x)CrSe–xVSe system were studied. The system was found to contain CuCr_{1 – x} V _x Se₂ solid solutions isostructural with CuCrSe₂. The solid-solution range and oxidation states of Cr and V were determined.     

Vapor Growth of Pb1 – x In x Te Crystals

Vapor growth of In-doped PbTe crystals by the sublimation–condensation and vapor–liquid–solid (VLS) processes is examined. Well-faceted Pb_{1 – x} In _x Te crystals with x = 0.04–0.06 are prepared by the sublimation method. The effects of the charge composition on the facial development and growth rate in the range 0 x 0.02 are discussed. The growth process at x 0.02 is shown to follow the VLS mechanism. Bulk Pb_{1 – x} In _x Te crystals with x 0.05 are grown by a vertical VLS process. The crystal composition is shown to depend significantly on the rate of ampule translation through the temperature field of the furnace and the separation between the evaporation and condensation zones. The longitudinal indium profiles in the crystals are correlated with growth kinetics.     

Temperature-Dependent Elastic Constants and Dielectric Properties of (Zn1 – x Cd x )3(P1 – y As y )2 Crystals

Crystals of constant-lattice-parameter (a const) and constant-thermal-expansion ( _a const) (Zn_{1 – x} Cd _x )₃(P_{1 – y} As _y )₂ solid solutions with 0.71 x 0.94 and 0.2 y 1 are prepared, and their elastic and dielectric properties are studied between 78 and 400 K. The elastic constants are found to decrease linearly with increasing temperature and to rise monotonically with increasing Cd and As content, up to x = 0.94 and y = 1. These findings are interpreted in terms of structural changes and bond rearrangement near the morphotropic structural transformation. Dielectric permittivity rises monotonically with temperature and solute concentration and shows a sharp upturn at x = 0.94 andy = 1. The extremely high dielectric permittivity is interpreted in terms of charge transfer between defect complexes responsible for deep levels in the band gap.     

Crystal Growth and Properties of Cd1 – x Zn x As2 Solid Solutions

Cd_{1 – x} Zn _x As₂ (x = 0.03, 0.05, 0.06) single crystals are grown by the Bridgman method, and their optical absorption spectra are measured. The introduction of Zn is shown to increase the band gap of CdAs₂, by up to 14 meV at x = 0.06. The highest content of ZnAs₂ incorporated into CdAs₂ is 6 mol %.     

Thermoelectric Properties of TlIn1 – x Yb x Te2 (0.01 ≤ x ≤ 0.09) Crystals

The thermoelectric properties of TlIn_{1 – x} Yb _x Te₂ (0.01 x 0.09) crystals are studied. The results indicate that the crystals possess high thermoelectric figures of merit in the range 500–700 K.     

Synthesis, Crystal Growth, and Acoustophotovoltaic Effect of TlIn1 – x Pr x Se2 and TlIn1 – x Pr x Te2

Procedures were developed for growing perfect TlIn_{1 – x} Pr _x Se₂ and TlIn_{1 – x} Pr _x Te₂ (0 x 0.08) single crystals. The growth charges were synthesized by a process involving partial cooling of a tilted, rotating tube. The crystals grown by the floating zone technique were found to readily cleave in two, mutually perpendicular mirror planes to give rectangular parallelepipeds. The crystals were shown to exhibit a sizeable acoustophotovoltaic effect: a combined action of radiation and sound waves produced an emf between the electrodes or a short-circuit current.     

Hydrothermal Synthesis and Transport Properties of FeS1-xTex (0 ≤ x ≤ 0.15) Single Crystals

Journal of Superconductivity and Novel Magnetism - In this work, a series of FeS1-xTex (0 ≤ x ≤ 0.15) single crystals were successfully synthesized by a hydrothermal method for the...     

Magnetic and Transport Properties of Single Crystalline K 0.8Fe 2 − x Ir x Se2

A series of K_0.8Fe_2?xIr _x Se₂ single-crystal compounds with nominal compositions x = 0, 0.01, 0.03, 0.05, 0.07, and 0.1 were successfully synthesized using self-flux method. It is found that the Ir doping in the present system will induce a suppression of the c-axis lattice constants. However, the zero-resistance temperatures, \(\mathrm {T}_{\mathrm {c}}^{\text {zero}}\) , are nearly maintained around 32 K for the samples with x ≤ 0.05, and it drops to 29 K for the one with x = 0.07. The superconductivity vanishes when the doping level reaches to 0.1. The hump in resistivity which corresponds to the transition from the insulating to metallic phase shifts towards low temperatures. However, the magnitude of the normal-state resistivity above 100 K for Ir-doped samples with x ≤ 0.05 is smaller than the one of the undoped sample, indicating the doping at Fe vacancy site. An onset transition temperature of 44 K has been observed in the ρ-T curve for K_0.8Fe_1.95Ir_0.05Se_2.     

Thermal Conductivity of Sr1 – xBaxF2 Single Crystals

Inorganic Materials - The thermal conductivity κ of single crystals of the Sr1–xBaxF2 fluorite solid solution series has been measured in the temperature range 50–300 K by an...     

Physicochemical Properties of (CuAlSe2)x(2ZnSe)1 – xSolid Solutions

(CuAlSe₂) _x (2ZnSe)_{1 – x} solid solutions were prepared by a single-zone method. According to x-ray diffraction characterization, the solid solutions had the chalcopyrite structure for x> 0.7 and sphalerite structure for x< 0.7. CuAlSe₂, ZnSe, and (CuAlSe₂) _x (2ZnSe)_{1 – x} crystals were grown by chemical vapor transport and were used for microhardness tests and transmission measurements near the fundamental edge. The results demonstrate that the microhardness and band gap of the solid solutions pass through a maximum and minimum, respectively.     

A Comparative Study of Fe1+?? Te1?x Se x Single Crystals Grown by?Bridgman and Self-flux Techniques

Single crystals of Fe_1+?? Te_1?x Se _x (0??x??0.5) were grown via both Bridgman and self-flux techniques. Large crystals of size ?10??50?mm could be obtained with the Bridgman method. The excess of iron, ????0.07, at interstitial sites was observed to deteriorate the superconductivity of the samples. Study of semiconducting and Curie?CWeiss-like behavior indicates that an appearance of a hump for Fe_1+?? Te_0.60Se_0.40 (????0.04) is more pronounced for the self-flux growth than for the Bridgman method. This was observed via measurement of the normal state of resistivity and magnetic susceptibility, which decrease with lower temperature. Furthermore, our results give evidence that the phase with x??0.40 is readily formed in the self-flux method despite the use of various ratios of initial mixtures.     

Laser deposition and study of CuInS2x Se2(1−x) crystals and films

Single-phase films of CuInS_2x Se_2(1−x) solid solutions with a chalcopyrite structure were deposited by laser evaporation of CuInS_2x Se_2(1−x) crystal targets (0≤x≤1). The structural and optical characteristics of the films depend on the chalcogen concentrations.     

Preparation and Magnetic Properties of CuCr1 – x Mn x S2 Solid Solutions

Phase relations in the CuS–CrS–MnS system (20 mol % MnS) were studied. The system was found to contain CuCr_{1 – x} Mn _x S₂ solid solutions isostructural with CuCrS₂. The solid-solution range and the oxidation states of Cr and Mn were determined.     

Dynamics of Photoexcited Carriers in Ba(Fe1−x Co x )2As2 Single Crystals with Spin-Density-Wave Ordering

We apply the femtosecond optical pump-probe spectroscopy to study the relaxation dynamics in photoexcited Co-doped Ba(Fe_1?x Co _x )₂As₂ single crystals in the underdoped spin-density wave (SDW) state region of the x?T phase diagram. Underdoped SDW samples with Co-0 % and Co-2.5 % show a bottleneck in the relaxation as a consequence of the partial charge gap opening in the orthorhombic SDW phase, similar to previous results in other SDW iron-pnictides. Moreover, the charge gap magnitude decreases with increasing doping. The sample with Co-5.1 % displays both a SDW ordering and superconductivity at low T. We were able to observe a 2-fold anisotropy in our samples, existing up to ～200 K, without any applied uniaxial stress. We associate the 2-fold symmetry breaking in nominally tetragonal phase with nematic ordering of the Fe d orbitals.     

Dielectric Properties of Melt-Grown Cd1 – xZnxTe Crystals

The real (") and imaginary (") parts of the complex dielectric permittivity of Cd_{1 – x} Zn _x Te (x= 0.1–0.2) crystals are measured as a function of temperature and frequency. The "-vs.-temperature data show a maximum, and " rises rapidly at about the same temperature. This behavior is interpreted in terms of compositional fluctuations, structural defects, and the associated internal electric fields.     

Composition and Electrical Properties of Hg x Cd1 – x S Whiskers

Data are presented on the morphology, composition, and electrical and photoelectric properties of Hg _x Cd_{1 – x} S (x = 0.25–0.6) whiskers.