@article {028_Cu57, title = {Nuclear magnetic moment of the $^{57}$Cu ground state (I=3/2$^-$, T$_{1/2}$=199.4 ms)}, journal = {Phys. Rev. Lett.}, volume = {96}, number = {10}, year = {2006}, pages = {1{\textendash}4}, address = {Department of Physics, Westmont College, Santa Barbara, CA 93108, United States}, abstract = {The nuclear magnetic moment of the ground state of Cu57(I?=3/2-,T1/2= 196.3ms) has been measured to be |?(Cu57)|=(2.00{\textpm}0.05)?N using the ?-NMR technique. Together with the known magnetic moment of the mirror partner Ni57, the spin expectation value was extracted as ??z =-0.78{\textpm}0.13. This is the heaviest isospin T=1/2 mirror pair above the Ca40 region for which both ground state magnetic moments have been determined. The discrepancy between the present results and shell-model calculations in the full fp shell giving ?(Cu57)?2.4?N and ??z ?0.5 implies significant shell breaking at Ni56 with the neutron number N=28. {\textcopyright} 2006 The American Physical Society.}, issn = {00319007 (ISSN)}, doi = {10.1103/PhysRevLett.96.102501}, author = {Minamisono, K. and Mantica, P.F. and Mertzimekis, T. J. and Davies, A.D. and Hass, M. and Pereira, J. and Pinter, J.S. and Rogers, W. F. and Stoker, J.B. and Tomlin, B.E. and Weerasiri, R.R.} }