J. Phys. IV France 07 (1997) C1-283-C1-286
Antisite Defects in Yttrium Iron GarnetP. Novák1, J. Englich2, H. Stepánková2, J. Kohout2, H. Lütgemeier3, K. Wagner3 and W. Tolksdorf4
1 Institute of Physics, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
2 Faculty of Mathematics and Physics, Charles University, V. Holesovickách 2, 180 40 Praha 8, Czech Republic
3 Forschungzentrum Jülich, 52425 Jülich, Germany
4 Hohenweg 3, 63691 Ranstadt, Germany
NMR of 57Fe nuclei is used to study the Ý antisite defects (yttrium ions on the sites nominally occupied by iron) in yttrium-iron garnet (YIG). In spectra of both tetrahedral and octahedral Fe3+ ions, satellite lines appear, corresponding to Fe3+ ions with this defect in their vicinity. NMR was measured on a number of nominally pure YIG samples - single crystals, thin films as well as polycrystalline samples. The content xY, per formula unit of the Y antisite defect (Ya) was determined from the amplitude of the satellite lines and it lies in the interval 0.001< xY < 0.03. In most cases the satellite lines caused by the Ya defect are obscured by the satellites originating from other impurities. In two high purity single crystals the satellites caused by Ya dominate, however. In the NMR spectra of these single crystals the satellite lines which correspond to the Fe3+ ions in seven different ctystallographically inequivalent positions with respect to the defect are resolved at low temperatures. Further unresolved satellites emerge from the main lines as the temperature is increased.
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