Exchange interactions in Y3Fe5-xCrxO12 fabricated by a sol-gel method

The Cr-containing YIG we examined, and the exchange interactions and site d istributions were studied by Fe-57 Mossbauer spectroscopy. The exchange par ameters for Y3Fe4.5Cr0.5O12 were J(ad) = -52.23 k(B), J(aa) = -27.85 k(B) a nd J(dd) = -39.16 k(B), and their values become larger as the amount of Cr decreases. in garnet. The results show that chromium in Y3Fe5-xCrxO12 compo unds (x = 0.0, 0.25, 0.5, and 1.0) occupy octahedral sites. The lowering of magnetic ordering temperature results from replacing. Fe3+ by Cr3+ in the octahedral sites. Mossbauer spectra can be analyses using 3 or 4 sets of si x Lorentzians with increasing amount of Cr3+. It results from the distribut ion (C-4(n)) of Fe3+ and Cr3+ at octahedral sites. The ratios of areas, a, d(1), d(2), d(3), in Y3Fe4.5Cr0.5O12 are 0.33, 0.22, 0.28, 0.14, respective ly.