Multiple ordered phases in the filled skutterudite compoundPrOs4As12

Abstract

Magnetization, specific heat, and electrical resistivity measurements were made on single crystals of the filled skutterudite compound $\mathrm{Pr}{\mathrm{Os}}_{4}{\mathrm{As}}_{12}$. Specific heat measurements indicate an electronic specific heat coefficient $\ensuremath{\gamma}\ensuremath{\sim}50--200\phantom{\rule{0.3em}{0ex}}\mathrm{mJ}∕\mathrm{mol}\phantom{\rule{0.2em}{0ex}}{\mathrm{K}}^{2}$ at temperatures $10\phantom{\rule{0.3em}{0ex}}\mathrm{K}\ensuremath{\leqslant}T\ensuremath{\leqslant}18\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, and $\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\mathrm{J}∕\mathrm{mol}\phantom{\rule{0.2em}{0ex}}{\mathrm{K}}^{2}$ for $T\ensuremath{\leqslant}1.6\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The combined measurements reveal the presence of two, or possibly three, ordered phases at temperatures below $\ensuremath{\sim}2.3\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and in fields below $\ensuremath{\sim}3\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. The low temperature phase displays antiferromagnetic characteristics, while the nature of the ordering in the other phase(s) has yet to be determined.