Free-energy analysis of the single-qand double-qmagnetic structures of neodymium

Abstract
A phenomenological model free energy is used to interpret the magnetic phase diagram of dhcp neodymium derived from recent neutron diffraction and thermal expansion measurements. First-order transitions at TN=19.9 K and at T2=19.1 K are to multidomain single-q and double-q modulated structures, respectively. The observed magnetic field dependence of these phases is in accord with the predictions of the model.