Granular Superconductivity in Hydrides Under Pressure

Abstract

It has been suggested that the measured magnetic properties of hydrides under pressure claimed to be high temperature superconductors indicate that the materials are granular superconductors. Such materials will show reduced or no magnetic field expulsion under field cooling, and will trap magnetic fields when the external magnetic field is removed. They will also exhibit hysteretic behavior in magnetoresistance and other transport properties. Here we point out that hysteresis in transport properties has never been reported for hydrides under pressure. Its presence, with the expected features, would indicate that the materials trap magnetic flux, hence that they can sustain persistent currents without dissipation, something that all superconductors can do. Conversely, its absence would indicate that these materials are not superconductors.

Влияние Внутригранульных Мейсснеровских Токов И Захваченного В Гранулах Потока На Эффективное Поле В Межгранульной Среде И Гистерезис Магнитосопротивления Гранулярного ВТСП

“…Для некоторых низкотемпературных сверхпроводников также наблюдаются эффекты, связанные с джозефсоновской связью между сверхпроводящими гранулами [35][36][37], или сверхпроводящими областями [38], и, как следствие, с реализацией двухуровневой сверхпроводящей системы. В работе [39] был предложен целенаправленный поиск гистерезисных эффектов в поведении магнитосопротивления " гидридных" сверхпроводников, которые могут сохранять сверхпроводимость до температур вблизи комнатной под высокими давлениями [13,14].…”

Influence of intragranular Meissner currents and magnetic flux trapped in granules on the effective field in the intergranular medium and the magnetoresistance hysteresis of a granular HTSC

“…For some low-temperature superconductors, effects related to the Josephson coupling between superconducting granules [35][36][37], or superconducting areas, are also observed [38], and, as a consequence, with the implementation of a two-level superconducting system. In the study [39], a purposeful search for hysteresis effects in the behavior of magnetoresistance of " hydride" superconductors that can maintain superconductivity to temperatures near room temperature under high pressures was proposed [13,14].…”