Reduction of iron(III) in annealed asbestos/chrysotile

Magnetic and structural properties of Bi substituted YIG with nominal formula of Bi _x Y_3???x Fe₅O₁₂ (x?=?0.0, 0.25, 0.5, 0.75, 1.00) prepared via Mechanochemical Processing (MCP) have been studied with Mossbauer spectroscopy, X-ray diffraction (XRD). The temperature dependence of sublattice magnetic hyperfine field for samples is analyzed. The a–d intersublattice superexchange found to be antiferromagnetic and increases from ??21.97 to ??25.79 k_B as Bi increases from 0.0 to 0.25. The a–a and d–d intrasublattice exchanges for sample x?=?0.0 are 13.18 and 10.55 k_B respectively while for sample x?=?0.25 a–a and d–d intrasublattice exchanges are 7.7 and 8.9 k_B respectively. The correlation of lattice constant and superexchange interaction are discussed.