μSR studies on the charge density waves in RE 5Ir 4Si 10

The series of intermetallic compounds RE ₅Ir ₄Si ₁₀ (RE=rare-earth) shows unusual charge density wave (CDW) order for temperatures lower than 160 K. This work presents a muon spin rotation (μSR) study, in zero external field, on single crystalline samples of the magnetic Er ₅Ir ₄Si ₁₀ ( T_CDW=155 and 55 K) and polycrystalline samples of Er ₅Ir ₄Ge ₁₀ (no CDW). The muon relaxation rate λ is strongly temperature dependent in both compounds. Furthermore, upon cooling below the CDW transition temperatures, a kink is seen in λ in Er ₅Ir ₄Si ₁₀. We interpret this result as a signature of the change in the density of states due to the establishment of the CDW.