LOCAL PICTURE OF THE MAGNETISM OF INTERMEDIATE VALENCE EUCU2-XAGXSI2 PHASES

With increasing silver concentration in EuCu2-xAgrSi2 phases the time-averaged europium 4f electronic configuration is driven closer toward the divalent state. The Eu-151 gamma-resonance absorption measurements performed in the temperature range 1.8-20 K revealed the presence of the magnetically ordered regions which vanish upon increasing the temperature. At x = 1.5 magnetic ordering extends over the whole volume of the sample, whereas the saturation hyperfine field is distinctly smaller than that for e.g. x = 0.25 sample.