Microscopic evidence of a field-induced critical spin-liquid state in a frustrated metal

Here, the authors use the transverse-field muon spin relaxation/rotation technique to microscopically map how a magnetic field (applied along the crystallographic $c$ axis) reshapes the quantum phases of the long-known frustrated kagome metal CePdAl. They reveal a field-induced spin-liquid state with quantum critical fluctuations---exceptionally rare in metallic frustrated systems. This powerful probe uncovers critical spin-liquid behavior with antiferromagnetic spin fluctuations, hidden to bulk and neutron measurements, establishing CePdAl as a benchmark for metallic frustration.