Abstract
The electrical resistivity of the dilute spin-glass alloys Au-0.10-at.% Mn, 0.15-at.% Mn, 0.10-at.% Fe, 0.13-at.% Fe, and Cu-0.15-at.% Mn has been measured from 1.2 to 40 K at pressures to 100 kbar. In these alloys the cooperative "locking-in" of the impurity spins at a temperature leads to a resistivity maximum at . Application of pressure is found to shift in a manner which is strongly system dependent: for Au:Mn, for Cu:Mn, and for Au:Fe. These results are shown to be clearly incompatible with the widely held belief that , where is the average strength of the Ruderman-Kittel-Kasuya-Yosida interaction, and indicate that is a function of both and , the Kondo temperature. This expectation is confirmed in a recent theory of Larsen who introduces an impurity-impurity interaction strength into the parquet approximation of the Kondo resistivity and obtains an explicit expression for . It is shown that both the sign and the magnitude of for the systems studied here are a natural consequence of both increasing and in all systems and depend on the relative magnitudes of and . In particular, one would expect to find in systems such as Au:Fe with relatively high Kondo temperatures. A further result of the analysis is that , lending support to the view that in these systems the long-range RKKY oscillations represent the dominant impurity-impurity interaction mechanism.
- Received 12 February 1976
DOI:https://doi.org/10.1103/PhysRevB.14.4368
©1976 American Physical Society