Abstract
Samples of the system LiNbO3-Fe2O3 prepared by water quenching and by the double-roller quenching method in the range up to 24 mol% Fe2O3 were investigated by Mössbauer and ESR spectroscopy. In the water quenched samples up to 11 mol% Fe2O3 only the Fe3+ and the Fe2+ valence states could be detected. The Fe2+ concentration decreased with increasing Fe2O3 content. Above 11 mol% Fe2O3 magnetically split Mössbauer spectra indicated the presence of Fe2O3 clusters. The isomer shift values of Fe3+ as a function of Fe2O3 concentration showed jumps at 6 and 11 mol% Fe2O3, whereas no significant changes could be detected in the quadrupole splitting values. The ESR data already exhibited the existence of isolated Fe3+ ions and of clusters with Fe-Fe distances less than 8 Å for the lowest Fe2O3 concentration. The cluster signal intensity increased with increasing Fe2O3 content. The roller quenched samples showed increased Fe2+ concentration as compared to the water quenched samples, which suggests that slow quenching results in iron oxidation and cluster formation. For low Fe2O3 concentrations a valence state change Fe3+⇄Fe2+ can easily be obtained by heat treatments in various atmospheres, whereas for higher Fe2O3 contents (9.8 mol%) precipitations ofα-Fe (in reducing atmosphere) and Fe2O3 (in air) could be observed in addition to the valence state changes of a remaining part of dissolved Fe ions. On the basis of the obtained results a model was suggested for the unusual behaviour of the lattice parameters observed in LiNbO3-Fe2O3.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
A. Räuber: InCurrent Topics in Materials Science, ed. by E. Kaldis (North-Holland, New York 1978) p. 481
W. Keune, S.K. Date, I. Dézsi, U. Gonser: J. Appl. Phys.46, 3914 (1975)
H. Engelmann, W. Gatzweiler, I. Dézsi, U. Gonser: Phys. Stat. Solidi (a)105, 219 (1988)
H. Takei, T. Katsumata: Mat. Res. Bull.17, 111 (1982)
B. Elouadi, F. Mouahid: To be published
H.S. Chen, C.E. Miller: Rev. Sci. Instrum.41, 1237 (1970)
See, e.g., U. Gonser (ed.):Mössbauer Spectroscopy, Topics Appl. Phys.5 (Springer, Berlin, Heidelberg 1978)
E. Kreber: Diplomarbeit, Universität des Saarlandes (1972)
T. Tomov, H. Engelmann, I. Dézsi, U. Gonser: To be published
H. Engelmann, U. Gonser: Ferroelectrics23, 97 (1980)
H. Engelmann, W. Gatzweiler, U. Gonser, I. Dézsi, A.G. Balogh: J. Non-Crystalline Solids89, 326 (1987)
W. Kündig, H. Bömmel, G. Constabaris, H. Lindquist: Phys. Rev.142, 2327 (1966)
See, e.g., V.I. Goldanskii, R.H. Herber:Chemical Applications of Mössbauer Spectroscopy (Academic, New York 1968)
H.-D. Pfannes, A. Putzka, J.F. Sampiao: Hyperfine Interactions28, 785 (1986)
J.B. Herrington, B. Dischler, J. Schneider: Solid State Commun.10, 509 (1972)
F. Gesmundo, C. de Asmundis: J. Phys. Chem. Solids34, 637 (1973)
F. Gesmundo, C. de Asmundis: J. Phys. Chem. Solids33, 1861 (1972)
R. Büscher, G. Lehmann: Z. Naturforsch.42a 67 (1987)
J.C. Chadwick, D.H. Jones, M.F. Thomas, C.J. Tatlock, M. Devenish: Hyperfine Interactions28, 541 (1986)
F. Gervais, J.F. Baumard:J. Phys. C.12, 1977 (1979)
J.L. Servoin, F. Gervais: Ferroelectrics25, 609 (1980)
H. Megaw:Crystal Structures: A Working Approach (Saunder, Philadelphia 1973)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Engelmann, H., Mouahid, F., Dézsi, I. et al. A Mössbauer and ESR study of LiNbO3-Fe2O3 for low Fe2O3 concentrations. Appl. Phys. A 48, 211–217 (1989). https://doi.org/10.1007/BF00619387
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00619387