Neutron diffraction study on heavy-fermion compoundCeCrGe3

We present a comprehensive powder neutron diffraction study on the heavy-fermion Kondo lattice system ${\mathrm{CeCrGe}}_{3}$ which orders ferromagnetically below ${T}_{C}=70\phantom{\rule{4pt}{0ex}}\mathrm{K}$. The neutron diffraction data corroborate the presence of magnetic Bragg peaks below ${T}_{C}$ which could be indexed with the propagation vector $\stackrel{P\vec}{k}=(0\phantom{\rule{4pt}{0ex}}0\phantom{\rule{4pt}{0ex}}0)$. Due to the presence of a very few magnetic reflections at low $T$, we have used ratio of intensities between the temperatures below (10 K) and above ${T}_{C}$ (80 K) to analyze magnetic structure, rather than the conventional Rietveld refinement method. Our analysis of the magnetic structure reveals an ordered magnetic moment of 1.1(1) ${\ensuremath{\mu}}_{B}$ for the Cr moments and 0.8(2) ${\ensuremath{\mu}}_{B}$ for the Ce moments where both are aligned in the $ab$ plane at $T=10\phantom{\rule{4pt}{0ex}}\mathrm{K}$. Remarkably, the presence of Ce moment is found to have a strong correlation with Cr moment and sets the Cr moments to order in the $ab$ plane rather than along the $c$ axis which was seen in $4{f}^{0}$ counterpart, i.e., ${\mathrm{LaCrGe}}_{3}$.