High quality GGG:Cr,Ca crystal for passive Q-switching Nd:garnet lasers has been grown by the Czochralski method. Thermal treatment of GGG crystals co-doped with Cr4+ and Ca2+ at different temperatures is investigated. The absorption spectra were resolved into different peaks, of modified Gaussian line-shape. Transition from octahedral sites to tetrahedral ones is thermally activated. An...

We report the discovery of a low-temperature phase transition in Bi2Sr2Ca(NixCu1−x)208 high temperature superconductor. This transition manifests itself as a sharp reduction of the thermal conductivity of the samples at a temperature T∗c ≈ 200 mK. The temperature dependence of the thermal conductivity changes dramatically from T with α between 1.6 and 1.75 above the transition to T-linear behav...

Molecular dynamic simulation is a powerful method that monitors all variations in the atomic level in explicit solvent. By this method we can calculate many chemical and biochemical properties of large scale biological systems. In this work all-atom molecular dynamics simulation of polyalanine (PA) was investigated in the presence of 0.224, 0.448, 0.673, 0.897 and 1.122 M of guanidinium chlorid...

In this paper, we report direct evidence of a structural transition in the organic superconductor k-~BEDT-TTF!2Cu@N~CN!2#Br near 80 K and the effect of disorder on the superconducting transition temperature. By cooling the sample from above 80 K, the interlayer magnetoresistance displays a bumplike feature, which increases sharply with increasing cooling rate. The rapidly cooled sample has a mu...

Methylammonium lead iodide perovskite has attracted considerable recent interest for solution processable solar cells and other optoelectronic applications. The orthorhombic-to-tetragonal phase transition in perovskite can significantly alter its optical, electrical properties and impact the corresponding applications. Here, we report a systematic investigation of the size-dependent orthorhombi...

In order to fabrication of transparent glass-ceramics with Li-mica nano crystals, the glasses with chemical composition of 94.9 mass% Li(1+x)Mg3AlSi3(1+x)F2 (x=0.5) with 5.1 mass% MgF2 were crystallized. The glasses were fabricated via the conventional melt-quenching technique. Mica crystals were precipitated in the glass phase by later heat treatment. Glass samples had glass transition tempera...

The temperature dependence of the irreversible phase transition from a two-dimensional gas to an ordered zero-dimensional solid on the Si(111)-7 × 7 surface was studied using photoemission spectroscopy. With increasing Na coverage, the two-dimensional Na gas, which is a state of highly mobile Na atoms, undergoes a phase transition into ordered zero-dimensional magic nanoclusters at room tempera...