Further evidence for the new collective magnetic dipole mode in heavy deformed nuclei

High-resolution inelastic electron scattering on ¹⁵⁴Sm, ¹⁵⁸Gd, ¹⁶⁴Dy, ¹⁶⁸Er and ¹⁷⁴Yb provides further evidence on the recently discovered low-lying magnetic dipole mode. We present here spectra, form factors and estimates for transition strengths and use mainly the interacting boson model (IBA-2) for comparison. We also show first results on the fragmentation of the strength of the new mode in ¹⁵⁶Gd.