The noncentrosymmetric half-Heusler semimetals RTBi (R=rare earth, T=Pt, Pd) have recently been proposed, according to electronic structure calculations, as plausible 3D topological insulators. The observation of superconductivity in the RPtBi and RPdBi series has added additional richness to these materials that compounds topological aspects of superconductivity and even magnetic order. The absence of inversion symmetry along with parity-violating antisymmetric spin-orbit coupling allows unconventional behaviours such as time-reversal symmetry breaking pairing state. To proof the unconventional superconducting properties of the half-Heusler materials, here we propose to study the magnetic and superconducting properties of RPtBi (R=Y and Lu) by a combination of zero-field and transverse-field µSR measurements. We ask for 6 days of MuSR beamtime for the proposed study.