Crystal structure and magnetic properties of Al15Fe9RE2 (RE = Gd, Tb) alloy

Al–Fe-rare earth (RE) ternary compounds have attracted much attention due to their excellent magnetic properties. Here, the crystal structure and magnetic properties of Al 15 Fe 9 RE 2 (RE = Gd, Tb) have been focused. Al 15 Fe 9 RE 2 (RE = Gd, Tb) are tetragonal structured crystals with space group I 4/ mmm (No. 139, tI 26). The lattice constants of Al 15 Fe 9 Gd 2 are a = 8.7441(1) Å and c = 5.0507(1) Å, and the lattice constants of Al 15 Fe 9 Tb 2 are a = 8.7333(1) Å and c = 5.0466(1) Å. Under the magnetic field of 50 Oe, the Curie temperatures T c of Al 15 Fe 9 Gd 2 and Al 15 Fe 9 Tb 2 are 347 K and 314 K, respectively. In a magnetic field of − 8 ~ 8 T at the temperature of 2 K, the maximum magnetic moment, remanence ( M r ), coercivity ( H c ), ( BH ) max and P H of Al 15 Fe 9 Gd 2 are 0.5 μ B /f.u., 0.32 μ B /f.u., 2.19 T, 51.05 MJ/m 3 and 81.08 kJ/m 3 ; the maximum magnetic moment of Al 15 Fe 9 Tb 2 is 2.30 μ B /f.u., M r is 1.29 μ B /f.u., H c is 1.52 T, ( BH ) max is 51.40 MJ/m 3 and P H is 303.09 kJ/m 3 . In addition, their magnetic characteristics show significant differences at 300 K temperature. The results show that Al 15 Fe 9 Tb 2 has the larger magnetic moment, remanent magnetization, ( BH ) max and P H , while Al 15 Fe 9 Gd 2 has the larger coercivity.