Campbell penetration depth in low carrier density superconductor YPtBi

Magnetic penetration depth, ${\ensuremath{\lambda}}_{m}$, was measured as a function of temperature and magnetic field in single crystals low carrier density superconductor YPtBi by using tunnel-diode oscillator technique. Measurements zero DC yield London ${\ensuremath{\lambda}}_{L}(T)$, but the applied signal includes Campbell ${\ensuremath{\lambda}}_{C}(T)$, which is characteristic length attenuation small excitation field, ${H}_{\mathrm{AC}}$, into Abrikosov vortex lattice due to its elasticity. Whereas dependent ${\ensuremath{\lambda}}_{C}$ exhibit ${\ensuremath{\lambda}}_{C}\ensuremath{\sim}{B}^{p}$ with $p=1/2$ most conventional unconventional superconductors, we found that $p\ensuremath{\approx}0.23\ensuremath{\ll}1/2$ rapid suppression pinning strength. From ${\ensuremath{\lambda}}_{C}(T,H)$, critical current ${j}_{c}\ensuremath{\approx}40\phantom{\rule{4pt}{0ex}}\mathrm{A}/{\mathrm{cm}}^{2}$ at 75 mK. This orders magnitude lower than superconductors comparable ${T}_{c}$.