Structural, Magnetic, and Mössbauer Studies of Transition Metal-Doped Gd₂Fe₁₆Ga_0.5TM_0.5 Intermetallic Compounds (TM = Cr, Mn, Co, Ni, Cu, and Zn)

The effect of transition metal substitution for Fe and the structural and magnetic properties of Gd₂Fe₁₆Ga_0.5TM_0.5 (TM = Cr, Mn, Co, Ni, Cu, and Zn) compounds were investigated in this study. Rietveld analysis of X-ray data indicates that all the samples crystallize in the hexagonal Th₂Ni₁₇ structure. The lattice parameters a, c, and the unit cell volume show TM ionic radii dependence. Both Ga and TM atoms show preferred site occupancy for 12j and 12k sites. The saturation magnetization at room temperature was observed for Co, Ni, and Cu of 69, 73, and 77 emu/g, respectively, while a minimum value was observed for Zn (62 emu/g) doping in Gd₂Fe₁₆Ga_0.5TM_0.5. The highest Curie temperature of 590 K was observed for Cu doping which is 15 and 5% higher than Gd₂Fe₁₇ and Gd₂Fe₁₆Ga compounds, respectively. The hyperfine parameters viz. hyperfine field and isomer shift show systematic dependence on the TM atomic number. The observed magnetic and Curie temperature behavior in Gd₂Fe₁₆Ga_0.5TM_0.5 is explained on the basis of Fe(3d)-TM(3d) hybridization. The superior Curie temperature and magnetization value of Co-, Ni-, and Cu-doped Gd₂Fe₁₆Ga_0.5TM_0.5 compounds as compared to pure Gd₂Fe₁₇ or Gd₂Fe₁₆Ga makes Gd₂Fe₁₆Ga_0.5TM_0.5 a potential candidate for high-temperature industrial magnet applications. View Full-Text