11B NMR study of single-crystal MgB2 in the normal conducting phase

Single-crystal magnesium diboride (MgB2) with a transition temperature to superconductivity of Tc = 38.4 K was investigated by quadrupole perturbed 11B nuclear magnetic resonance in a field of 9 T in the normal conducting phase. Experimental values for the electric field gradient tensor, the magnetic shift tensor, and the nuclear spin–lattice relaxation time for boron were obtained. The anisotropy of the nuclear spin–lattice relaxation and the magnetic shift were determined. A positive sign of the electric field gradient was found. Our results show good agreement with published theoretical calculations and in part with experimental nuclear magnetic resonance data from polycrystalline samples.