Effect of Magnetic Impurities on Superconductivity in LaH₁₀

Abstract

Polyhydrides are a novel class of superconducting materials with extremely high critical parameters, which is very promising for sensor applications. On the other hand, a complete experimental study of the best so far known superconductor, lanthanum superhydride LaH10, encounters a serious complication because of the large upper critical magnetic field HC2(0), exceeding 120–160 T. It is found that partial replacement of La atoms by magnetic Nd atoms results in significant suppression of superconductivity in LaH10: each at% of Nd causes a decrease in TC by 10–11 K, helping to control the critical parameters of this compound. Strong pulsed magnetic fields up to 68 T are used to study the Hall effect, magnetoresistance, and the magnetic phase diagram of ternary metal polyhydrides for the first time. Surprisingly, (La,Nd)H10 demonstrates completely linear HC2(T) ∝ |T – TC|, which calls into question the applicability of the Werthamer–Helfand–Hohenberg model for polyhydrides. The suppression of superconductivity in LaH10 by magnetic Nd atoms and the robustness of TC with respect to nonmagnetic impurities (e.g., Y, Al, C) under Anderson's theorem gives new experimental evidence of the isotropic (s‐wave) character of conventional electron–phonon pairing in lanthanum decahydride.

Quantifying Nonadiabaticity in Major Families of Superconductors

“…If measuring techniques are limited to the magnetoresistance measurements, (which was the case in the field of highly-compressed near-room temperature superconductors (NRTS) [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ], until recent experimental progress by Minkov et al [ 51 , 52 ]), can be estimated by the equation [ 53 ]: where is the ground state amplitude of the superconducting energy gap, which is varying in a reasonably narrow range , so that the ballpark value for can be estimated. For instance, can be deduced from magnetoresistance measurements [ 54 ] and the electron–phonon coupling strength constant, , can be assumed to be the average value of values calculated by first-principles calculations [ 55 , 56 ].…”

Superconducting Be2SH3 with kagome hydrogen at high pressure

“…29 Yet, thus far, only a few ternary hydrides have been experimentally synthesized, including the low-T c of BeReH 9 (7 K at 100 GPa) 30 and Li 5 MoH 11 (6.5 K at 160 GPa). 31 Recently, experimentalists have successfully synthesized several high-T c ternary hydrides (La,Y)H 10 (253 K at 183 GPa), 32 (La,Ce)H 9 (178 K at 110 GPa or 176 K at 100 GPa) 33,34 and (La,Nd)H 10 (148 K at 170 GPa), 35 which further demonstrates the superconductive potential of ternary hydrides. Of these, superconductors based on sulfur hydride have been abundantly reported, such as C-S-H, [36][37][38][39] Y-S-H, 40,41 Se-S-H, 42 B-S-H, 43 Fe-S-H, 44 Ca-S-H, 45 even including noble gases like Xe-S-H. 46 High pressures are known to stabilize the compounds that are not accessible under ambient conditions.…”

Nodeless Superconductivity in Kagome Metal CsV3Sb5 with and without Time Reversal Symmetry Breaking

“…Recently, the superfluid density has been shown to be related to the self-field critical current density ( J c , sf ), i.e., the transport critical current density in the absence of an external magnetic field. − Thus, by measuring the temperature dependence of the critical current, the gap symmetry and the coupling strength can be extracted. Measurement of J c , sf has been demonstrated under pressure. , Therefore, the examination of J c , sf provides a novel route to probe the superconducting gap and superfluid density at any pressure.…”