First on-line $\beta$-NMR on oriented nuclei: magnetic dipole moments of the $\nu{p}^{-1}_{1/2}; 1/2^-$ ground state in $^{67}$Ni and $\pi{p}^{+1}_{3/2}; 3/2^-$ ground state in $^{69}$Cu

The first fully on-line use of the angular distribution of $\beta$ - emission in detection of NMR of nuclei oriented at low temperatures is reported. The magnetic moments of the single valence particle, intermediate mass, isotopes $^{67}$Ni($\nu{p}^{-1}_{1/2}$; 1/2$^{-}$) and $^{69}$Cu($\pi{p}^{+1}_{ 3/2}$; 3/2$^{-}$) are measured to be +0.601(5)$\mu_{N}$ and +2.84(1)$\mu_{N}$ respectively, revealing only a small deviation from the neutron $p_{1/2}$ single-particle value in the former and a large deviation from the proton $p_{3/2}$ single-particle value in the latter. Quantitative interpretation is given in terms of core polarization and meson-exchange currents.