Recently, the existence of superconductivity in $\mathrm{ H_{ 3}S}$ and other high-pressure hydrides is called into question, because of some flawed magnetic measurements. In Ref.[1] the SCPC model is proposed, where strong pinning of vortices is due to long columnar defects in $\mathrm{ H_{ 3}S}$ - with lengths $\mathrm{ L}$ of the order of vortex lengths $\mathrm{ L_{ v}}$. Two relevant type of experiments in magnetic fields are explained by this model: (1) Reduction (with respect to standard superconductors) of the thermal broadening of resistance ($\mathit{ TBR}$) in magnetic field $\mathrm{ h=H/H_{ c2}}$, $\mathrm{ \mathrm{ \delta t_{ c}(h)}}$, is governed by the small parameter $\mathrm{ C=}$$\mathrm{ \xi_{ 0}}/\mathrm{ L}$. The $\mathit{ TBR}$ measurements give, that in $\mathrm{ H_{ 3}S}$ there is a large shift of the irreversible line $\mathrm{ B_{ irr}(T)}$ towards the $\mathrm{ B_{ c2}(T)}$ line. (2) In ZFC (zero field cooled) experiments on penetration of the magnetic field ($\mathit{ PMF}$) in $\mathrm{ H_{ 3}S}$ [3], the latter reaches the center of a superconducting disk at much larger external fields, i. e. for $\mathrm{ B_{ 0}\gg B_{ c1}}$. The later is due to the pronounced pinning of vortices, but not to the Meissner effect. The calculated $\mathrm{ T}$- dependence of the penetrated, perpendicular $\mathrm{ B_{ \perp}(T)}$ and parallel $\mathrm{ B_{ \parallel}}(\mathrm{ T})$, magnetic field into the sample is in satisfactory agreement with the experimental results for $\mathrm{ H_{ 3}S}$ in [3], where $\mathrm{ B_{ \perp}>B_{ \parallel}}$. Problems related to measurements of the Meissner effect in $\mathrm{ H_{ 3}S}$ are also discussed. The SCPC model, applied on the bulk $\mathrm{ H_{ 3}S}$ sample, predicts, that the latter is a high-$\kappa$ superconductor.
Categories: cond-mat.supr-con cond-mat.str-el