Residual short-range order in the heavy fermion compound CeInCu₂

Abstract

By using the X-ray diffraction technique, residual shortrange order was detected in CeInCu 2 , cerium dicopper indium, which is known to be a heavy fermion compound. In spite of the long-range order of this substance, diffuse scattering exhibiting short-range order was observed at room temperature. The correlation parameters obtained showed that an incorrectly occupied lattice site has a tendency to gather atoms of different species at the neighboring sites along the h111i directions. Thus, the disordered region would form a cluster composed of several disordered atoms. Furthermore, a chain-type correlation which has a period of 20± 23 A Ê along the same directions was indicated. The superstructure-like feature of the disordered atoms hardly increases the residual resistivity. It is consistent with the behavior of the residual resistivity under high pressure.

Crystal Growth and Intergrowth Structure of the New Heavy Fermion Materials CeIrIn5 and CeRhIn5

“…Nearly periodic &&disorder'' might have no or very little e!ect on the residual resistivity. For example, in the heavy fermion compound CeInCu , nearly periodic &&disorder'' (observed as almost periodically modulated di!use intensity in the reciprocal space) does not in#uence the residual resistivity, even if it remains at low temperature (18). The residual resistivity of CeRhIn and CeIrIn is low, of the order 1 -cm, suggesting that they are nearly defect-free materials (17).…”