Comment on "phase diagram of reentrant and magnetic-field-induced superconducting states with Kondo impurities in bulk and proximity-coupled compounds"

The Meissner effect induced in a normal metal in close contact with a superconductor is known to weaken at very low temperatures, and to be restored by the application of a moderate magnetic field. This reentrant behavior was recently interpreted as resulting from the presence of Kondo impurities in the normal metal, with calculated concentrations on the order of 100 ppm. We show here that in fact the presence of magnetic impurities in the normal metal at such concentrations is ruled out by the absence of a minimum of resistivity in the same samples down to 2 K.