  Well-protected magnetization, tunable quantum states and long coherence time
are desired for developing magnetic molecules as qubits quantum information
processing and storage. Based on the first-principles calculations and dynamic
simulations, we demonstrate that endohedral fullerene molecule Ir@C28 has
stable magnetization, huge magnetic anisotropy energy (> 30 meV per molecule)
and bias-tunable structural phases. In particular, qubits based on Ir@C28 may
have coherence times up to several mS at high temperature (~100K) after full
consideration of spin-vibration couplings. These results suggest a new strategy
of using endohedral fullerene as qubits for technological breakthroughs.
