SUPERCONDUCTIVITY AND MAGNETISM IN LA1-XTMXRU3SI2 (X-LESS-THAN-OR-EQUAL-TO-0.2)

Type II-superconducting properties of La1-xTmxRu3Si2 (x less-than-or-e qual-to 0.2) have been studied as a function of temperature and magnet ic field. The critical line H(c2)(T) of the phase diagram has been det ermined for magnetic field H less-than-or-equal-to 11 kG. The depressi on rate dT(c)/dx = -7K per atomic fraction of Tm impurities is unexpec tedly large, and attributable to hybridization of the conduction elect ron states with the 4f level of the trivalent Tm ions.