Structural, magnetic, and electrical properties of (Pr<inf>0.5</inf>Er<inf>0.5</inf>)<inf>2</inf>Fe<inf>17-x</inf>Al<inf>x</inf>

An x-ray diffraction study of (Pr0.5Er0.5)2Fe17-xAlx (0≤x≤10) shows an expansion of its unit cell with x. The crystal structure changes from hexagonal Th2Ni17 to rhombohedral Th2Zn17 at x = 6. The magnetic moment decreases by increasing the Al concentration. This effect may be due to the charge transfer from Al to the 3d band of Fe. The Curie temperatures are found to increase with Al up to x = 3 and then decrease up to x = 10, and the possible underpinning mechanisms are discussed. X-ray diffractograms of the magnetically aligned samples indicate that the easy magnetization directions of the samples with x = 1,2,3, and 4 lie on a cone about the c axis. Electrical resistivity measurements show that the residual resistivity increases drastically with the Al concentration. The temperature coefficient of resistivity becomes almost zero for intermediate Al concentrations. © 1995 American Institute of Physics.