Large Room Temperature Bulk DNP of C via P1 Centers in Diamond.

We use microwave-induced dynamic nuclear polarization (DNP) of the substitutional nitrogen defects (P1 centers) in diamond to hyperpolarize bulk C nuclei in both single crystal and powder samples at room temperature at 3.34 T. The large (>100-fold) enhancements demonstrated correspond to a greater than 10 000-fold improvement in terms of signal averaging of the 1% abundant C spins.