Robust but disordered collapsed-volume phase in a cerium alloy under the application of pulsed magnetic fields

Abstract

We report synchrotron x-ray powder diffraction measurements of Ce${}_{0.8}$La${}_{0.1}$Th${}_{0.1}$ subject to pulsed magnetic fields as high as 28 T. This alloy is known to exhibit a volume collapse upon cooling at ambient pressure, which is a modification of the $\ensuremath{\gamma}$-$\ensuremath{\alpha}$ transition in elemental cerium. Recently, it has been suggested on the basis of field-cooled resistivity and pulsed-field magnetization measurements that the volume collapse in this alloy can be suppressed by the application of magnetic fields. Conversely, our direct diffraction measurements show a robust collapsed phase, which persists in magnetic fields as high as 28 T. We also observe nanoscale disorder in the collapsed phase, which increasingly contaminates the high-temperature phase upon thermal cycling.