HYPERFINE FIELDS OF MERCURY IN SINGLE-CRYSTALLINE COBALT

The combined hyperfine interaction of mercury in a hexagonal close-pac ked cobalt single crystal was measured using the e(-)-gamma perturbed angular correlation technique with the Hg-197 and Hg-199 probes, witho ut applied magnetic field. The magnetic and quadrupole coupling consta nts of the 5/2(-) levels in both Hg-197 and Hg-199 were measured with extremely high precision, omega(L)(Hg-197)=951(9) Mrad/s, omega(L) (Hg -199)=1039(10) Mrad/s, v(Q) (Hg-197)=3.7(5) MHz and v(Q) (Hg-199)=32(2 ) MHz. Using the well-known g factors and quadrupole moments of the re spective levels, the magnetic hyperfine field, \H-hf(HgCo)\=581(12) kG , and the electric field gradient, \V-zz(HgCo)\=2.0(3)x10(17) V/cm(2), were derived. The importance of using these hyperfine probes for stud ying the microscopic structure of cobalt-based multilayers is introduc ed and discussed.