Crystal and magnetic structures of LaNi5-xMnx

The crystallographic and magnetic properties of LaNi5-xMnx with x=1, 1.5, a nd 2, have been investigated using x-ray and neutron diffraction, vibrating sample magnetometer and superconducting quantum interference device measur ements. All the samples crystallize in the hexagonal CaCu5-type (P6/mmm) st ructure. Manganese atoms preferentially occupy the 3g site in the LaNi5 str ucture. The bulk magnetization of the LaNi5-xMnx powder samples decreases r apidly as nickel is replaced by manganese. A ferrimagnetic model is applied to describe the magnetic structure of the LaNi5-xMnx samples for x=1.5 and 2. A ferromagnetic model gives the best fit of the neutron diffraction dat a for the LaNi4Mn sample. (C) 2000 American Institute of Physics. [S0021-89 79(00)77408-1].