Mössbauer Study of Hyperfine Fields in MnZn Ferritess

Abstract

The hyperfine field in Mnl-,Zn, Fe,O, ferrites is studied in dependence on x and temperature. A six:nearest-neighbours model used in evaluating the Mossbauer spectra leads to convex magnetization functions if the number of Zn nearest neighbours is > 3. Das Hyperfeinfeld in Mnl-an, Fe,O,-Ferriten wurde in Abhlingigkeit von x und der Temperatur untersucht. Fur die Auswertung der MoDbauerspektren wurde ein Modell mit sechs nachsten Nachbarn benutzt, das eine konvexe Magnetisierungsfunktion liefert, w enn die Zahl der nachsten Zn-Nachbarn groBer als 3 ist. I ) On leave from the Institute of Nuclear Physics, Cracow. 2, On leave from the A1 Azhar University, Cairo. 9 . 132 L. CSER et, al.

Study of the Sublattices Magnetisations in Mn0.6Zn0.4Fe2O4 by Neutron Diffractometry and Mössbauer Spectrometry

“…2). Recently Czer et al [17] proposed a static model for the interpretation of the Mossbauer spectra of manganese zinc ferrites. I n their model the spectra are composed by up t o four ideal Zeeman spectra with quite different internal field temperature dependences, related to the zinc ions distribution.…”

Mössbauer, infrared, and X-ray studies of the MnZn ferrites

“…In view of the area under peaks of the A-and B-sites (Table 1) and the well-known site preference [20] of ions, where the recoil fractions fA and fs for the absorber are relatively small, it is clear that Mn2+ ions give rise to inversion in the spinel [l to 111. The cation distribution proposed for this ferrite system is given in Table 2.…”

Magnetic Field Distribution Analysis of the Broadened Mössbauer Spectra of Zinc Ferrite

“…This kind of behsviour needs chemical disorder or multiple sites for iron, and is not observed in the normal spinel ZnFe,O, ; b) if, as observed in ZnFe,O, (Fig. l), broadening has very much decreased near 0 OK, it may be assumed that H, and the reduced magnetization are proportional with the same coefficient everywhere in the sample: a.t the B site of the partly inverse spinels Co, Mn, Mg ferrites [6], and of Zn-Mn ferrite [7] a spreading of exchange interactions is evoked to explain the observed broadening. I n FeF, relaxation phenomena have been evoked [8] : however the broadening depends on the quality of the preparation and it seems more reasonable to admit a spreading of T, due to some inhomogeneity of the samples [9].…”