相关论文: Low-temperature phase transitions in some quaterna…

Substitutions of the zirconium and tin ions along with the indium-niobium and iron-niobium complexes for titanium in the barium modified NBT solid solutions impact the formation of phases in the process of the solid state synthesis and the…

In the substitutionally disordered narrow-gap semiconductor Pb_{1-x}Ge_xTe, a finite-temperature cubic-rhombohedral transition appears above a critical concentration $x \approx 0.005$. As a first step towards a first-principles…

In this work we present an experimental study of structure and phase stability in ternary Cu-Sn-In alloys around 55 at.% Cu in the temperature range 100^{\circ}C < T < 550^{\circ}C. We have followed in real-time the sequence of phase…

Phase-change materials based on Ge-Sb-Te alloys are widely used in industrial applications such as nonvolatile memories, but reaction pathways for crystalline-to-amorphous phase-change on picosecond timescales remain unknown. Femtosecond…

The Ge(001)-(2 1 0 3)-Pb surface reconstruction with a lead coverage of 5/3 monolayer is on the borderline between the low-coverage covalently-bonded and high-coverage metallic lead overlayers. This gives rise to an unusual low-temperature…

Polycrystalline CuMo$_{1-x}$W$_x$O$_4$ solid solutions were studied by resonant X-ray emission spectroscopy (RXES) at the W L$_3$-edge to follow a variation of the tungsten local atomic and electronic structures across thermochromic phase…

Full pattern Le-Bail refinement using x-ray powder diffraction profiles of Sr1-xCaxTiO3 for x=0.02, 0.04 in the temperature range 12 to 300 K reveals anomalies in the unit cell parameters at 170, 225 K due to an antiferrodistortive (cubic…

Solid He-4 is viewed as a nearly perfect Debye solid. Yet, recent calorimetry measurements by the PSU group (J. Low Temp. Phys. 138, 853 (2005) and Nature 449, 1025 (2007)) indicate that at low temperatures the specific heat has both cubic…

Formation of phases during the solid state synthesis of the barium-modified NBT solid solutions, with substitutions of zirconium and tin ions for titanium are investigated. The synthesis is a multi-step process which is accompanied by the…

The results of differential-thermal analysis of various samples as well as dielectric measurements of solid solutions $TlIn_{1-x}Fe_x^{56,57}S_2$ are presented. It has been established that phase transitions become blurred and shift to low…

The classification of structural phase transitions as displacive or order-disorder in character is usually based on spectroscopic data above the transition. We use single crystal x-ray diffraction to investigate structural correlations in…

We investigate the influence of order parameter fluctuations on the transition between normal and mixed superconducting states at low temperatures. We show that in case of clean quasi-two-dimensional superconductors the transition can be…

All solid phases of bismuth under pressure, but one, have been experimentally found to superconduct. From Bi-I to Bi-V, avoiding Bi-IV, they become superconductors and perhaps Bi-IV may also become superconductive. To investigate the…

The correlation between magnetic properties and microscopic structural aspects in the diluted magnetic semiconductor Ge$_{1-x}$Mn$_{x}$Te is investigated by x-ray diffraction and magnetization as a function of the Mn concentration $x$. The…

Specific heat studies of the Sr$_{1-x}$Ba$_x$Mn$_{1-y}$Ti$_y$O$_3$ polycrystalline samples performed by the relaxation and DSC methods over the temperature range 2 - 450 K are reported. Anomalies accompanying the…

We report the discovery of a low-temperature phase transition in Bi_2Sr_2Ca(Ni_xCu_{1-x})_20_8 high temperature superconductor. This transition manifests itself as a sharp reduction of the thermal conductivity of the samples at a…

We have carried out torsional oscillator experiments on solid $^4$He at temperatures between 1.3K and 1.9K. We discovered phenomena similar to those observed at temperatures below 0.2K, which currently are under debate regarding their…

The zero temperature, or quantum, metal-superconductor phase transition is studied in disordered systems in dimension greater than two. A effective local field theory is developed that keeps all soft modes or fluctuations explicitly. A…

Nuclear quadrupole resonance (NQR) on copper nuclei has been applied for studies of the electronic properties of quasi-two-dimensional low-temperature superconductor CuS (covellite) in the temperature region between 1.47 and 290 K. Two NQR…

We present a theoretical survey of ferromagnetic transition temperatures in cubic (III,Mn)V semiconductors based on a model with $S=5/2$ local moments exchange-coupled to itinerant holes in the host semiconductor valence band. Starting from…