Implantation studies of low-energy positive muons in niobium thin films

Here we study the range of ke V positive muons μ+ implanted in Nb2O5 (x nm)/Nb(y nm)/SiO2(300 nm)/Si [x=3.6nm,3.3nm; y=42.0nm,60.1nm] thin films using low-energy muon spin spectroscopy (LE-μSR). At implantation energies 1.3keV≤E≤23.3keV, we compare the measured diamagnetic μ+ signal fraction fdia. against predictions derived from implantation profile simulations using the TRIM.SP Monte Carlo code. Treating the implanted μ+ as light protons p+, we find that simulations making use of updated stopping cross section data are in good agreement with the LE-μSR measurements, in contrast to parameterizations found in earlier tabulations. Implications for other studies relying on accurate μ+ stopping information are discussed.