Magnetic coupling between the different phases in nanocrystalline Fe-Si-B studied by small angle neutron scattering

Kohlbrecher, J.; Wiedenmann, A.; Wollenberger, H.

doi:10.1007/s002570050411

Cited by 51 publications

(33 citation statements)

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“…From the ®t of the magnetic scattering signal, it is found that the density of magnetic moments at the surface ( i m ) is much smaller than in the crystallite and in the amorphous matrix. This fact, which has been con®rmed also by small-angle neutron scattering measurements using polarized neutrons and magnetic contrast variation (Wiedenmann, 1999), can explain the breakdown of direct magnetic exchange coupling between the Fe 80 Si 20 precipitates and the amorphous matrix just below the Curie temperature T c of the amorphous matrix, as suggested by previous experiments (Kohlbrecher et al, 1997). The value of a m from the nonlinear ®t shown in Table 2 is larger than the value of 2.86 Â 10 14 m À2 calculated from the magnetic saturation ®eld of 1.24 T of the amorphous matrix.…”

Section: Applicationmentioning

confidence: 50%

A small-angle neutron scattering model for polydisperse spherical particles with diffusion zones and application to soft magnetic metallic glass

Heinemann

Hermann

Wiedenmann³

et al. 2000

J Appl Cryst

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An analytical expression for the small-angle neutron scattering intensity of diluted systems of polydisperse spherical particles, with diffusion zones, embedded in a matrix is presented. It is used within a nonlinear regression procedure to analyse small-angle neutron scattering experiments with polarized neutrons on an Fe 73.5 Si 15.5 B 7 CuNb 3 alloy. The results for the nuclear and magnetic scattering length densities allow veri®cation of the inhibitor concept introduced for the explanation of the limited sizes of precipitates developing during nanocrystallization. In the case of amorphous Fe 73.5 Si 15.5 B 7 CuNb 3 alloy, the observed nanocrystals of the Fe 3 Si type are surrounded by an Nb-enriched shell, which stops the growth of the precipitates. With the results of polarized neutron scattering experiments, it is shown that magnetic and nuclear smallangle neutron scattering signals have the same origin. Additionally, the precision of the ®ts is improved by complementary use of polarized neutrons.

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Section: Applicationmentioning

confidence: 50%

A small-angle neutron scattering model for polydisperse spherical particles with diffusion zones and application to soft magnetic metallic glass

Heinemann

Hermann

Wiedenmann³

et al. 2000

J Appl Cryst

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“…In SANSPOL experiments, apart of the nuclear interaction there is a contribution of the magnetic moment of the atoms that come from its interaction with the magnetic moments of the neutrons [27][28][29][30][31]. During measurements a constant magnetic field in the direction perpendicular to the direction of the incident neutron beam is applied to the sample.…”

Section: Sanspolmentioning

confidence: 99%

Structural analysis of Fe–Mn–O nanoparticles in glass ceramics by small angle scattering

Raghuwanshi

Harizanova

Tatchev

et al. 2015

Journal of Solid State Chemistry

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Magnetic nanocrystals containing Fe and Mn were obtained by annealing of silicate glasses with the composition 13.6Na 2 O-62.9SiO 2 -8.5MnO-15.0Fe 2 O 3-x (mol %) at 580 °C for different periods of time. Here, we present Small Angle Neutron Scattering using Polarized neutrons (SANSPOL) and Anomalous Small Angle X-ray Scattering (ASAXS) investigation on these glass ceramic samples. Analysis of scattering data from both methods reveals the formation of spherical core-shell type of nanoparticles with mean sizes between 10 nm and 100 nm. ASAXS investigation shows the particles have higher concentration of iron atoms and the shell like region surrounding the particles is enriched in SiO 2 . SANSPOL investigation shows the particles are found to be magnetic and are surrounded by a nonmagnetic shell-like region.

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“…The modulus of the total particle moment ͉p͉ and hence the argument xϭ͉p͉͉H͉/(k B T) depend on the diameter, D, of the particle via For noninteracting single-domain particles embedded in a nonmagnetic matrix, it was shown that the anisotropic part B(s) has a completely magnetic origin: 10 B͑s ͒ϭ͕1Ϫ3L͑ x ͒/x͖m 2 ͑ s ͒, ͑12͒…”

Section: ͑3͒mentioning

confidence: 99%

Formation of magnetic nanocrystals in a glass ceramic studied by small-angle scattering

Lembke

Hoell

Kranold

et al. 1999

Journal of Applied Physics

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The formation of nanosized crystallites of magnetite, Fe 3 O 4 , by heat treatment of a glass containing iron oxide was investigated. The magnetic properties of the glass ceramic manufactured strongly depend on the heat treatment conditions. The evolution of size distribution and volume fraction of the nanocrystallites formed was studied by small-angle x-ray scattering ͑SAXS͒. The size distribution of the nanocrystalline phase turned out to show bimodal shape. The possibility of magnetic contrast variation offered by small-angle neutron scattering ͑SANS͒ was utilized in order to distinguish the small-angle scattering of magnetite from the scattering contributions of nonmagnetic iron containing crystallites that can additionally be formed during the heat treatment. The results obtained reveal that both size grades of particles observed in the size distribution are superparamagnetic consisting of magnetite. The evolution of the volume fraction of magnetite in dependence on the heat treatment was found to be correlated with the magnitude of the specific saturation magnetization of the glass ceramic. The volume size distributions derived from magnetic SANS revealed peaks at smaller radii in relation to those from nuclear SANS and SAXS data. Therefore, the existence of a nonmagnetic surface layer is suggested that surrounds the magnetically active core of the magnetite nanocrystals.

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Magnetic coupling between the different phases in nanocrystalline Fe-Si-B studied by small angle neutron scattering

Cited by 51 publications

References 0 publications

A small-angle neutron scattering model for polydisperse spherical particles with diffusion zones and application to soft magnetic metallic glass

A small-angle neutron scattering model for polydisperse spherical particles with diffusion zones and application to soft magnetic metallic glass

Structural analysis of Fe–Mn–O nanoparticles in glass ceramics by small angle scattering

Formation of magnetic nanocrystals in a glass ceramic studied by small-angle scattering

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