Magnetic Dipole Moments of First 2+ States in Even Osmium Nuclei Recoil-Implanted in Nickel

The ion-implantation-perturbed-angular-correlation technique has been used to measure the g factors of the first 2⁺ excited states of four even osmium nuclei in a ferromagnetic nickel host. The observed angular precessions were: ωτ(¹⁹²Os)=0.22+/-0.01, ωτ(¹⁹⁰Os)=0.277+/-0.009, ωτ(¹⁸⁸Os)=0.39+/-0.03, and ωτ(¹⁸⁶Os)=0.38+/-0.08. The angular precession result for ¹⁹²Os is in excellent agreement with the results of perturbed-angular-correlation measurements in nickel using radioactive sources. It was found that the internal field seen by the osmium nuclei implanted in nickel is in good agreement with the value obtained by room temperature NMR techniques. The available direct lifetime measurements for ^186,188Os and lifetimes extracted from B(E2) values for ^190,192Os are used to obtain the gyromagnetic ratios: g(¹⁹²Os)=0.39+/-0.03, g(¹⁹⁰Os)=0.39+/-0.03, g(¹⁸⁸Os)=0.29+/-0.03, and g(¹⁸⁶Os)=0.24+/-0.05.