Muon trapping at substitutional Ti in Fe

Iron doped with 400 ppm Ti was investigated by the muon spin rotation method. Below 70 K and above 180 K the normal 50 MHz signal of pure Fe was observed. However, in a small temperature range around 100 K a completely different frequency with v = 112 MHz shows up. This signal is attributed to muons trapped at Ti in Fe. The experiment yields the hyperfine field B_hf and the binding energy E_B for the trapped muons. We find B_hf = 93(5) mT and E_B = 81(5) MeV.