Level structure of $^{69}$Zn and the nature of yrast excitations near N=40

The region of nuclei around $^{68}$Ni$_{40}$, with its closed proton shell and closed neutron harmonic-oscillator sub-shell, continues to be of much interest as recent data indicate that the stabilizing effects of the N=40 gap are rather localized in N and Z. There is evidence for the onset of collectivity and strong polarization of the $^{68}$Ni core in neighboring nuclei of the region. With two protons and one neutron hole in $^{68}$Ni, the structure of $^{69}$Zn provides an opportunity to learn about the nature of its yrast excitations, and to identify the orbitals responsible for polarization effects. Excited states in $^{69}$Zn were populated with deep-inelastic reactions of a $^{70}$Zn beam at 430 MeV on a thick 197Au target. A level scheme, with states built on the previously known 13.76(2)-hour isomer, will be presented, along with comparisons with the results of shell-model calculations.