Magnetic and structural properties of SmCo_6.75-xFe_xZr_0.25 compounds

Bulk alloys of SmCo_6.75-xFe_xZr_0.25, where x = 0, 0.27, 0.41, and 0.54 were prepared by arc-melting. The alloys were characterized by X-ray diffraction, vibrating sample magnetometer, and SQUID magnetometer. X-ray diffraction shows that these compounds form the hexagonal TbCu₇-type structure for x<0.67 and for large values of x (x≥0.67) the hexagonal TbCu₇-type structure cannot be formed. The lattice parameters (a and c) are dependent on the iron concentration. The unit cell volume is found to increase with x which is due to the larger atomic volume of Fe. X-ray diffraction and magnetization measurements on magnetically aligned samples show that all the samples studied have uniaxial anisotropy. The saturation magnetization increases with x at both room temperature and 5 K. The Curie temperature for these compounds is about 770 °C for all values of x under investigation.