Spin Response Of Magnetic Dipole Transitions In Gd-156 And Dy-164

Intermediate energy proton scattering has been used to probe the spin part of the recently discovered low-lying isovector magnetic dipole transitions in the rotational rare earth nuclei 156 Gd and 164 Dy. A large spin response is found in 164 Dy, whereas in 156 Gd the results are consistent with the picture of a predominantly convective excitation. The results are discussed in the context of the IBA-2 model and recent RPA calculations.