Nuclear mass and size corrections to the magnetic shielding

We derive finite nuclear mass and finite nuclear size corrections to the magnetic shielding in light ions. These corrections are important for the accurate determination of nuclear magnetic moments. We correct several previous formulas for the nuclear mass corrections and present improved results for the magnetic shielding in ${}^1$H, ${}^3$He${}^{+}$, and ${}^3$He. Finally, we obtain an ${}^3$He atomic magnetic moment, which serves as an accurate probe to measure magnetic fields.