Динамическая восприимчивость нанокомпозита пористое стекло/Ga-In-Sn в области сверхпроводимости

Interest to studies of gallium alloys increased recently in relation to their prospective applications for self-healing superconducting connections and wires. Special attention is focused on superconductive properties of nanostructured alloys. In the present work we studied the ac susceptibility of a porous glass/Ga-In-Sn nanocomposite within the temperature range from 1.9 to 8 K at bias fields up to 5 T. Two superconducting phase transitions were revealed with temperatures of 5.6 and 3.1 K. Phase diagrams were created. Positive curvature of the parts of critical lines was demonstrated and treated within the framework of a proximity effect model. Vortex activation barriers were found from shifts of the maxima of the imaginary parts of susceptibility with changing the ac frequency. A bend was shown on the field dependence of the activation barriers.

CHANGE IN PROPERTIES OF DIFFUSION-HARDENING SOLDER IN DEPENDENCE ON THE COMPOSITION OF THE LIQUID METAL COMPONENT

В статье обсуждается изменение свойств диффузионно-твердеющего припоя в зависимости от состава жидкометаллической компоненты на основе легкоплавких сплавов галлия: галлий-олово, галлий-индий-олово и галлий-олово-цинк при взаимодействии с порошком сплава медь-олово (ПМОСФ5) подвергнутых низкотемпературной (125 °С) и высокотемпературной (500 °С) термической обработке. Механические свойства оценены измерением микротвердости, а термические исследованы методом дифференциально-термического анализа. Термическая обработка при высоких температурах способствует переходу припоя в равновесное состояние, при этом происходит значительное увеличение твердости. По графикам дифференциальнотермического анализа рассчитаны экзотермические эффекты. Методом рентгенофазового анализа определены образующиеся в результате диффузионного твердения фазы. Показано, что при различных температурах обработки образуются разные фазы - наноразмерные интерметаллические соединения. Экспериментально доказано улучшение механических свойств диффузионно-твердеющего припоя при наличии цинка растворенного в галлиевом жидком сплаве. The article discusses the change in the properties of diffusion-hardening solder in dependence on the composition of the liquid metal component based on low-melting gallium alloys: gallium-tin, gallium-indium-tin and gallium-tin-zinc when interacting with the Spherical copper-tin alloy powder (SCTAP5) subjected to low-temperature (125 °С) and high-temperature (500 °С) heat treatment. The mechanical properties were evaluated by measuring the microhardness, and the thermal properties were studied by differential thermal analysis. Heat treatment at high temperatures promotes the transition of the solder to an equilibrium state, with a significant increase in hardness. The thermal effects of heat treatment of diffusion-hardening solders are calculated and compared. The phases formed as a result of hardening are determined by X-ray phase analysis. It is shown that different phases and nanoscale intermetallic compounds are formed at different processing temperatures. The improvement of the mechanical properties of diffusion-hardening solder in the presence of zinc dissolved in a gallium liquid alloy has been experimentally proved.

Engineering new limits to magnetostriction through metastability in iron-gallium alloys

Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare-earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. Fe1−xGax alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC Fe1−xGax alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A Fe1−xGax − [Pb(Mg1/3Nb2/3)O3]0.7−[PbTiO3]0.3 (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10−5 s m−1. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.

Reduction of the transition resistance of demountable contact joints using gallium alloys

The article studies the possibility of reducing the transition resistance of demountable electrical contact joints in laboratory conditions by using multicomponent gallium alloys. The relevance of the chosen topic is attributed to the need for reducing energy losses and improve the reliability of a contact network.