Mossbauer hyperfine field

Fig. 6.2 Theoretical Fe Mossbauer relaxation spectra for longitudinal relaxation with the indicated relaxation times and with a hyperline field that can assume the values 55 T. The symmetry direction of the axially symmetric EFG is assumed parallel to the magnetic hyperfine field. (Reprinted with permission from [9] copyright 1966 by the American Physical Society)...

Mossbauer spectrum is then proportional to the average value of the hyperfine field which is given by... 

Fig. 6.17 The average magnetic hyperfine field at low temperatures, obtained from Mossbauer spectra of coated and uncoated 8 nm particles of a-Fe203 (Fig. 6.16). The lines are linear fits to the data in accordance with (6.23) and (6.25). (Reprinted with permission from [77] copyright 2006 by the American Physical Society)...

McCammon et al. have studied fine nickel particles using Ni Mossbauer spectroscopy [22]. The measured average hyperfine field of 10 nm particles at 4.2 K was 7.7 T for nickel foil, it was found to be 7.5 T. Application of an external magnetic field of 6 T caused a reduction of the hyperfine splitting to 1.5 T as a consequence of the negative hyperfine field at Ni nuclei. 

Radioactive Ru is dilutely doped in Fe304. The value of the magnetic hyperfine field (at the Ru nucleus) obtained by TDPAC at 10 K (—16 T) is essentially in agreement with that derived from the Mossbauer spectrum at 5 K (14.5 T). The negative sign of means that the Ru ions... 

Apart from the already mentioned (Sect. 7.6.1) determination of the nuclear g-factors of W through Mossbauer measurements with tungsten diluted in an iron foil [225, 229] where a hyperfine field at the W site of 70.8 2.5 T was... 

A Japanese group [297] measured the hyperfine field at Ir nuclei in the alloys Feo.yPto.aJrx (0.03 < x < 0.2) using the Ir (73 keV) Mossbauer transition, in order to understand the mechanism associated with the decrease of the magnetic moment (and negative hyperfine field) in these alloys. The isomer shift was found to increase with increasing x, which could be rationalized by the contraction of the lattice volume. 

Alloys of Pd-Au-Fe (2 at%) Mossbauer effect in Fe and Au, study of band filling, hyperfine fields, isomer shifts... 

Fig. 7.5 Room temperature Mossbauer spectra and distributions of magnetic hyperfine fields for four goethites, decreasing in crystallinity from a to d (Murad, 1982a, with permission).

Fig. 7.6 Mossbauer spectra at 4.2 K and hyperfine field distributions of natural 6- (LC31) and 2-line (LC2) ferrihydrite from ferri-ferrous spring waters (Murad, 1988, with permission).

Fig. 17.3 Magnetic hyperfine field (left) and width of the outer lines of the sextets (right) obtained from Mossbauer spectra of ferritins, isolated from human spleen, limpet hemolymph and bacterial cells Pseudomonas aeruginosa) as a function of temperature (Webb St.Pierre, 1989 with permission).

Fig. 50. Mossbauer spectra (CEMS) and hyperfine-field distributions of a Terfecohan/(Yo.2Feo.g) multilayer (a) the as-deposited film, (b) after annealing at 250°C and (c) 350°C. After Due (2002).

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