Neutron diffraction study of C14-Laves-phase, TbMn2 and DyMn2

The temperature dependence of powder neutron diffraction for hexagonal C14-Laves-phase TbMn2 and DyMn2 has been measured. Ferromagnetism and antiferromagnetism coexist in TbMn2. The ferromagnetic component continues up to 60 K, whereas the antiferromagnetic component takes its maximum value at around 55 K, begins to decrease above 55 K and vanishes at around 80 K. The magnetic unit cell of the antiferromagnetism is twice of the chemical one in an a-direction. A presumable magnetic structure has been discussed. For C14-DyMn2, no other structure is observed except for the ferromagnetic one which disappears at around 35 K.