Microhardness of the YbAgxIn1−xCu4 alloy system

We report Vickers microhardness measurements on flux grown single crystals of the YbAgxIn1−xCu4 alloy system. Although sample dependent, the microhardness exhibits a clear concentration dependence: in general, it decreases with x. The lattice parameter as a function of x exhibits a similar behavior. For x < 0.5, where the lattice parameter is almost constant, the microhardness exhibits a weak enhancement. Similar concentration dependence of the lattice parameter, resistivity and microhardness allows us to conclude that the microhardness reflects the evolution of the YbAgxIn1−xCu4 alloy system towards more metallic character with increasing x. C 2005 Springer Science + Business Media, Inc.