Magnetic ground state of KCr3As3

Many unconventional superconductors, such as cuprates and iron-based materials, display spin-glass states in the underdoped regime, which usually coexist and/or compete with unconventional superconductivity. Here, we performed zero-field (ZF) and longitudinal-field (LF) muon spin-rotation experiments (μSR) on quasi-one-dimensional KCr3As3. Our ZF μSR measurements reveal a large decrease (about 1/3) in the initial asymmetry below 10 K, indicating the presence of a magnetic phase transition. The analysis of the LF μSR results illustrates this transition at the same temperature, and points it to a spin-glassy state. These results would, potentially, confirm unconventional superconductivity in K-Cr-As and related compounds.