NEUTRON-SCATTERING STUDY OF THE MAGNETIC-ORDERING IN HONIAL

Polycrystalline sample of HoNiAl has been studied by powder neutron di ffraction. The existence of two magnetic phases with transition temper atures T-c = 13 K and T-l = 5 K has been confirmed. The magnetic struc ture of both phases contains ferro- and antiferromagnetic components o f the magnetic moments. The antiferromagnetic component with the propa gation vector (1/2, 0, 1/2) is parallel to the c-axis for T > T-l and lie in the basal plane far T < T-l. At any temperature the ferromagnet ic component is along the c-axis.