Etude par diffraction neutronique à 0,04 K de la perovskite d'aluminium et d'holmium

At very low temperatures HoAlO₃ displays magnetic properties characteristic of singlet ground-state systems with the existence of a coupled electronic nuclear ordering induced by the hyperfine interactions. Neutron diffraction measurements at 0.04 K show the presence of an antiferromagnetic arrangement G_xA_y. The thermal dependence of the 001 reflexion leads to a value of the critical temperature of 0.16 K.