Phenomenological investigation of structural, magnetic, and dielectric properties of holmium substituted gadolinium iron garnet.

We have prepared (Gd_1−xHo_x)₃Fe₅O₁₂ (x = 0.0 to 1.0) samples by solid-state reaction method at a sintering temperature of 1400 °C for 8 hours. The formation of single phase is verified with refinement of X-Ray Diffraction patterns using I a 3 - d space group. The lattice constant, bond length, and F e a - O - F e d bond angle are showing a decreasing trend with Ho substitution which also results in decrease in ferrimagnetic (FIM) transition temperature from 553 K (x = 0.0) to 543 K (x = 1.0) . Additionally all the samples show magnetic compensation in between 145 K to 295 K. The hysteresis loops shows magnetic saturation at ambient as well as low temperature. We have also observed an increment in coercivity as we go from room temperature to 5 K because of higher magnetic anisotropy at low temperature. The Nyquist plots reveals the depressed semicircle behavior which shows the deviation of these systems from ideal Debye type relaxation. Moreover, ac conductivity is analyzed and it decreases with Ho substitution due to the drop in charge carriers concentration. All the samples represent magneto-electric coupling about ferrimagnetic transition temperature. [ABSTRACT FROM AUTHOR]