Ga-In Alloy Segregation within a Porous Glass as Studied by SANS.

Nanolattices can play the role of templates for metals and metallic alloys to produce functional nanocomposites with particular properties affected by nanoconfinement. To imitate the impact of nanoconfinement on the structure of solid eutectic alloys, we filled porous silica glasses with the Ga-In alloy, which is widely used in applications. Small-angle neutron scattering was observed for two nanocomposites, which comprised alloys of close compositions.

Magnetic Studies of Superconductivity in the Ga-Sn Alloy Regular Nanostructures.

For applications of nanolattices in low-temperature nanoelectronics, the inter-unit space can be filled with superconducting metallic alloys. However, superconductivity under nanoconfinement is expected to be strongly affected by size-effects and other factors. We studied the magnetic properties and structure of the Ga-Sn eutectic alloy within regular nanopores of an opal template, to understand the specifics of the alloy superconductivity.

SANS Studies of the Gallium-Indium Alloy Structure within Regular Nanopores.

Potential applications of nanolattices often require filling their empty space with eutectic metallic alloys. Due to confinement to nanolattices, the structure of phase segregates in eutectic alloys can differ from that in bulk. These problems are poorly understood now.

The morphologic correlation between vortex transformation and upper critical field line in opal-based nanocomposites.

In this study, we investigate metallic nanocomposites to elucidate the properties of nanostructured conventional superconductors. Liquid tin, indium, and mercury are loaded into opal matrices by high pressure up to 10 kbar. The opal templates preserve the 3D dendritic morphology of confined superconducting metals to model a dendritic second phase with particular grain shape in bulk superconductors observed by a DualBeam microscope.

C NMR of DIPAC and DIPAB organic ferroelectrics.

The diisopropylammonium chloride (CHClN, DIPAC) and diisopropylammonium bromide (CHBrN, DIPAB) molecular crystals are recently discovered ferroelectrics with sufficiently high spontaneous polarization and Curie temperature. We performed first studies of these crystals by C NMR. CP MAS spectra were collected within large temperature ranges covering the Curie points.

Dielectric properties of an organic ferroelectric of bromide diisopropylammonium embedded into the pores of nanosized AlO films.

The study presents experimental results for investigating linear and nonlinear dielectric properties of nanocomposites based on bromide diisopropylammonium (CHNBr, DIPAB) and aluminum oxide films (AlO) with pore diameter of 330, 100 and 60 nm. It was indicated that the phase transition was blurred and shifted toward lower temperatures. This anomaly became more significant with decreasing pore size.

Liquid-liquid transition in supercooled gallium alloys under nanoconfinement.

NMR studies of the thermal evolution of the Ga-In-Sn and Ga-In liquid alloys embedded into opal matrices were carried out. Temperature dependences of the gallium lineshape, shift of the resonance frequency (Knight shift), and intensity were obtained upon cooling down to the alloy freezing and subsequent warming. A second high-frequency Ga NMR signal emerged for both alloys upon cooling, the NMR line intensity transferring gradually into this additional signal.

Polymorphism of Metallic Sodium under Nanoconfinement.

(23)Na NMR studies of sodium nanoparticles confined to porous glass with the 3.5 nm mean pore size were carried out. The emergence of the second component of the NMR line was observed below 240 K that evidences the occurrence of another modification of metallic sodium.

Atomic mobility in nanostructured liquid Ga-In alloy.

Nuclear spin relaxation and the Knight shift for (71)Ga, (69)Ga, and (115)In isotopes were studied by nuclear magnetic resonance (NMR) in liquid gallium-indium alloy confined to porous glass and alloy surface film and were compared with the bulk counterparts. Drastic spin relaxation acceleration under nanoconfinement was observed for the three isotopes. Quadrupole and magnetic contributions to spin relaxation were separated for gallium and indium isotopes using the experimental data obtained, which allowed, in particular, the evaluation of correlation times of atomic mobility.

Superconductivity and structure of gallium under nanoconfinement.

Superconductivity and crystalline structure were studied for two nanocomposites consisting of gallium loaded porous glasses with different pore sizes. The superconducting transition temperatures were found to differ from those in known bulk gallium modifications. The transition temperatures 7.

Phase transitions in K(1-x)Na(x)NO(3) embedded into molecular sieves.

Dielectric studies of molecular sieves MCM-41 filled with K(1-x)Na(x)NO(3) salts (x = 0, 0.05 and 0.10) were carried out and compared with results obtained for their bulk counterparts.

Spin-lattice relaxation enhancement in liquid gallium confined within nanoporous matrices.

Nuclear spin relaxation for liquid gallium embedded into nanoporous matrices was found to accelerate remarkably compared to the bulk melt. NMR measurements on two gallium isotopes showed that the dominant mechanism of relaxation was changed from magnetic to quadrupolar and the relation rate depended on the Larmor frequency. The correlation time of electric field gradient fluctuations was estimated using data for quadrupolar relaxation contribution and was found to increase drastically compared to bulk, which corresponded to slowing down mobility in confined liquid gallium.

Impurity nuclear spin-lattice relaxation suppression and charge exchange of chromium ions in a gamma-irradiated ruby crystal.

The possibility of directly separating and measuring the impurity and lattice contributions to nuclear spin-lattice relaxation under the condition of a steady-state magnetic saturation is demonstrated in the particular case of 27Al nuclei in a gamma-irradiated ruby crystal. Contributions from trivalent and charge-exchanged chromium ions to impurity nuclear relaxation were separated. The number of charge-exchanged chromium ions was found.