  Recently, researches performed by two groups have revealed that the magnetar
spin-down energy injection model with full energy trapping can explain the
early-time light curves of SN 2010gx, SN 2013dg, LSQ12dlf, SSS120810 and
CSS121015, but fails to fit the late-time light curves of these Superluminous
Supernovae (SLSNe). These results imply that the original magnetar-powered
model is challenged in explaining these SLSNe. Our paper aims to simultaneously
explain both the early- and late-time data/upper limits by considering the
leakage of hard emissions. We incorporate quantitatively the leakage effect
into the original magnetar-powered model and derive a new semi-analytical
equation. Comparing the light curves reproduced by our revised magnetar-powered
model to the observed data and/or upper limits of these five SLSNe, we found
that the late-time light curves reproduced by our semi-analytical equation are
in good agreement with the late-time observed data and/or upper limits of SN
2010gx, CSS121015, SN 2013dg and LSQ12dlf and the late-time excess of
SSS120810, indicating that the magnetar-powered model might be responsible for
these SLSNe and that the gamma ray and X-ray leakage are unavoidable when the
hard photons were down-Comptonized to softer photons. To determine the details
of the leakage effect and unveil the nature of SLSNe, more high quality
bolometric light curves and spectra of SLSNe are required.

High Energy Astrophysical Phenomena