New Island ofμsIsomers in Neutron-Rich Nuclei around theZ=28andN=40Shell Closures

New isomeric states in the neutron-rich nuclei near the $Z=28\mathrm{}$ and $N=40\mathrm{}$ shell closures have been identified among the reaction products of a $60.3A$ MeV ${}^{86}\mathrm{Kr}$ beam on a ${}^{\mathrm{nat}}\mathrm{Ni}$ target. From the measured isomeric decay properties information about the excited states and their nuclear structure has been obtained. The isomerism is related mostly to the occupation of the neutron $g_{9/2}$ orbital, an intruder level in the $N=3\mathrm{}$ $\mathrm{fp}$ shell. It is illustrated with the decay properties of ${}^{69}{\mathrm{Ni}}^m$, ${}^{70}{\mathrm{Ni}}^m$, and ${}^{71}{\mathrm{Cu}}^m$ interpreted within the nuclear shell model.