Interplay between magnetism and superconductivity in metallic hydrogen and hydrides at high pressure

Abstract

The detailed analysis of resistive and magnetic measurements with sulfur hydrides at high pressure is performed. The hydrogen system at high pressure can exhibit ferromagnetic (FM) as well as superconducting (SC) properties with layered structure. The onset temperature of resistive transition at 200 K in metallic sulfur hydrides corresponds to magnetic (AF SDW) phase transition rather than SC one. SC transition in these sulfur hydrides occurs only when magnetic (AF SDW) phase transition is over (~ 40 K). The SC mechanism in metallic sulfur hydrides is not conventional but corresponds to Keldysh-Kopaev model characteristic for systems with coexistence of dielectric and SC pairing.

Clear evidence against superconductivity in hydrides under high pressure

“…Instead, we have recently argued that the experimental evidence presented so far does not provide conclusive proof of superconductivity in any of these materials [12][13][14][15][16][17][18][19][20][21][22][23]. Others have also questioned experimental [24][25][26] and theoretical [27,28] evidence for superconductivity in some of these materials. Therefore, the very existence of high temperature superconductivity in hydrides under pressure is now in doubt.…”

Clear evidence against superconductivity in hydrides under high pressure

“…Instead, we have recently argued that the experimental evidence presented so far does not provide conclusive proof of superconductivity in any of these materials [10][11][12][13][14][15][16][17][18][19]. Others have also questioned experimental [20][21][22] and theoretical [23,24] evidence for superconductivity in some of these materials. Therefore, the very existence of high temperature superconductivity in hydrides under pressure is now in question.…”

Clear evidence against superconductivity in hydrides under high pressure

“…Instead, we have recently argued that the experimental evidence presented so far does not provide conclusive proof of superconductivity in any of these materials [9][10][11][12][13][14][15][16][17][18]. Others have also questioned experimental [19][20][21] and theoretical [22,23] evidence for superconductivity in some of these materials. Therefore, the very existence of high temperature superconductivity in hydrides under pressure is now in question.…”