MAGNETIC-PROPERTIES OF ND2CO17-XALX COMPOUNDS STUDIED BY MAGNETIC MEASUREMENTS AND NEUTRON-DIFFRACTION

The magnetic properties of Nd2Co17-xAlx compounds (x = 2, 3 and 4) wer e studied by means of neutron diffraction and magnetic measurements. T he refinement results of the neutron powder diffraction patterns show that there is a slight preference for the Al atoms to occupy the 18h s ite in the rhombohedral Th2Zn17 structure adopted by these compounds. By contrast, the 9d site is completely avoided by the Al atoms. From m agnetic measurements it is derived that there is an almost linear decr ease of the Curie temperature with Al concentration accompanied by a s omewhat less strong decrease of the saturation moment at 4.2 K. For th e compound with x=4 we observed a spin reorientation transition slight ly above room temperature.