Multiple polyamorphisms and superconductivity in a Ce-based metallic glass

Metallic glasses (MGs) are in the cutting edge of research in materials science for both their unique properties that yield a variety of commercial applications like MEMS, pressure sensors or biocompatible prosthesis [1] and for fundamental studies on the nature of the glass transition and other related phenomena [2]. The main characteristics of MGs are the lack of long-range order, the random close packed atomic configuration and their excellent elastic properties (high compressive strength and large elasticity). The rare earth (RE) elements have played an important role, as a minor additions and as main constituents, in the design of new alloys with an exceptional glass forming ability that allow the production of bulk pieces, the so-called bulk metallic glasses (BMGs) [3]. Moreover, these rare earth based bulk metallic glasses (REBMGs) present several attracting features that make them promising materials for engineering applications such as polymerlike thermoplastic behaviour (Ce(La)-based), hard magnetic properties (Nd(Pr)-based), polyamorphism (Ce-based) or superconductivity (La-based).
In this presentation we will present coupled high pressure diffraction and resistivity measurements on the Ce70Al10Ni10Cu10 alloy. In this system a series of pressure induced polyamorphic transformations have been observed and the differences in the transport properties of the different amorphous phases are discussed and correlated to their microstructure. Especially we will concentrate in the low temperature behaviour of the transport properties where we observe an increase of the resistivity associated with the Kondo effect. Application of hydrostatic pressure induces a reduction followed by the disappearance of the Kondo behaviour and the appearance of superconductivity at higher pressure. We will discuss and analyze the correlation of the polyamorphic transitions with the anomalies in the transport properties.