  The odd-odd 54;56;58;60;62;64Mn isotopes (Z = 25) were studied using
bunched-beam collinear laser spectroscopy at ISOLDE, CERN. From the measured
hyperfine spectra the spins and magnetic moments of Mn isotopes up to N = 39
were extracted. The previous tentative ground state spin assignments of
58;60;62;64Mn are now firmly determined to be I = 1 along with an I = 4
assignment for the isomeric states in 58;60;62Mn. The I = 1 magnetic moments
show a decreasing trend with increasing neutron number while the I = 4 moments
remain quite constant between N = 33 and N = 37. The results are compared to
large-scale shell-model calculations using the GXPF1A and LNPS effective
interactions. The excellent agreement of the ground state moments with the
predictions from the LNPS calculations illustrates the need for an increasing
amount of proton excitations across Z = 28 and neutron excitations across N =
40 in the ground state wave functions from N = 37 onwards.
