High magnetic fields up to 105 T have been utilized in deriving the upper critical field $B_{\mathrm{c}2}$ of ${\mathrm{LaFeAsO}}_{1-x}{\mathrm{H}}_x$ throughout the wide temperature range below $T_{\mathrm{c}}$. Resistivity measurements demonstrate that $B_{\mathrm{c}2}$ behaves differently in samples with $x=0.12$ (SC1) from those with 0.32 (SC2). In SC1, the two-band model assuming $s$-wave pairing gives a good fitting with a repulsive intraband interaction and dominant interband coupling. In SC2, we have to assume an attractive intraband interaction with weak interband coupling, which in fact suggests a non-$s$-wave pairing in view of the strong Coulomb repulsion. These results support the possibility that SC1 and SC2 have different pairing symmetries.

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• High magnetic fields
• Multiband superconductivity
• Superconductivity
• High-temperature superconductors
• Iron-based superconductors
• Type-II superconductors
• Unconventional superconductors
• Resistivity measurements