Mild hydrothermal synthesis and ferrimagnetism of Pr3Fe5O12 and Nd3Fe5O12 garnets

Two pure light rare earth iron garnets Pr3Fe5O12 and Nd3Fe5O12 single crystals were synthesized under mild hydrothermal conditions and structurally characterized by single crystal and powder X-ray diffraction methods. Both compounds crystallize in cubic space group Ia3̄d with lattice parameters a=12.670(2) Å for Pr3Fe5O12 and a=12.633(2) Å for Nd3Fe5O12, respectively. The synthesis of compounds was studied with regard to phase evolution and morphology development with hydrothermal conditions. We proposed the formation mechanisms and formulated a reasonable explanation for their growth habits. Ferrimagnetic Curie temperatures which have been inferred from thermo-magnetization curves were 580 K for Pr3Fe5O12 and 565 K for Nd3Fe5O12, and the transitions of long range order were also evidenced by differential scanning calorimetry method. The result of magnetic properties has shown that moments of the large radius Pr3+ and Nd3+ ions are parallelly coupled with net moments of iron ions.