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The magnetic anisotropy in amorphous ${\mathrm{Fe}}_{82}$${\mathrm{B}}_{12}$${\mathrm{Si}}_{6}$ (METGLAS \textregistered{} 2605S) has been studied by the determination of both surface and bulk properties using M\"ossbauer, x-ray, and density measurements. Upon annealing above 650 K, a substantial anisotropy with an easy direction perpendicular to the ribbon plane develops. It is proposed that the origin of this out-of-plane anisotropy, also observed for other amorphous ribbons, is a compressive

Hyperfine M\"ossbauer spectra of ${\mathrm{Fe}}^{57}$ in cobaltous oxide in the pure and vacated forms are measured below the N\'eel temperatures. The hyperfine spectra of CoO(I) are of a pure ${\mathrm{Fe}}^{2+}$ type and give a pattern characteristic of magnetic and quadrupole hyperfine interactions. They are analyzed by diagonalizing a 4\ifmmode\times\else\texttimes\fi{}4 magnetic and quadrupole interaction matrix of the first excited state of an ${\mathrm{Fe}}^{57}$ nucleus and fitting eight

The existence of two forms of cobaltous oxide, CoO(I) and CoO(II), has been established by M\"ossbauer, x-ray, and chemical techniques. CoO(I) has the NaCl structure as determined by a well-resolved powder x-ray pattern. Its density is measured to be 6.4 g/${\mathrm{cm}}^{3}$ from both x-ray and direct macroscopic experiments. ${\mathrm{Fe}}^{57}$ M\"ossbauer lines in CoO(I), doped with ${\mathrm{Co}}^{57}$, show only ${\mathrm{Fe}}^{2+}$ when determined by either the isomer shift or the hyperfi

The transformation from the as-quenched amorphous to the crystalline state of ${\mathrm{Fe}}_{82}$${\mathrm{B}}_{12}$${\mathrm{Si}}_{6}$ (METGLAS\textregistered{} 2605S) has been investigated by M\"ossbauer spectroscopy, x-ray diffraction, and density measurements. The first step of the transformation is found to be structural relaxation during which atomic rearrangements towards a more stable amorphous state take place. In the second step, crystalline Fe-9 at.% Si alloy precipitates out until t

M\"ossbauer studies of antiferromagnetic FeC${\mathrm{O}}_{3}$ below and above the N\'eel temperature show an asymmetric line broadening, and a constant value of 184 kOe of the magnetic hyperfine field from $0 \mathrm{to} \frac{1}{2}{T}_{N}$. These phenomena are explained using an Ising model with slow electron relaxation. The relaxation rate decreases with decreasing temperature, suggesting a spin-lattice relaxation. The N\'eel temperature was found to be (38.3\ifmmode\pm\else\textpm\fi{}0.3)\i

M\"ossbauer spectra of ferrimagnetic ${\mathrm{Fe}}_{7}$${\mathrm{Se}}_{8}$ have been taken at various temperatures ranging from liquid-nitrogen temperature to the specimen's N\'eel point. Three sets of six-line hyperfine patterns were obtained and assigned to three magnetically nonequivalent sites of a superstructure of the crystal. Isomer shifts indicate nearly ${\mathrm{Fe}}^{2+}$ for all three sites. Change of sign of quadrupole splittings above and below 130 \ifmmode^\circ\else\textdegree\f

The magnetic anisotropy in amorphous Fe40Ni38Mo4B18 (METGLASR 2826MB) has been studied by the determination of both surface and bulk properties using Mössbauer, x-ray, and density measurements. The onset of bulk crystallization is preceded by surface crystallization in conjunction with which magnetic anisotropies with easy directions perpendicular and parallel to the ribbon plane develop in the ribbon bulk and surface layers, respectively. It is proposed that the anisotropies, also observed for

The amorphous state of ferromagnetic ${\mathrm{Fe}}_{75.4}$${\mathrm{B}}_{14.2}$${\mathrm{Si}}_{10.4}$ and its crystalline phases after crystallization have been studied by M\"ossbauer spectroscopy and magnetic-moment measurements. The average hyperfine field ${H}_{\mathrm{hf}}(T)$ of the amorphous state shows a temperature dependence of $\frac{[{H}_{\mathrm{hf}}(T)\ensuremath{-}{H}_{\mathrm{hf}}(0)]}{{H}_{\mathrm{hf}}(0)=\ensuremath{-}0.30{(\frac{T}{{T}_{c}})}^{\frac{3}{2}}\ensuremath{-}0.16{(\

Amorphous ${\mathrm{Fe}}_{82}$${\mathrm{B}}_{12}$${\mathrm{Si}}_{6}$ in ribbon form has been investigated over a large temperature range from 2 to 796 K using the M\"ossbauer technique. The values of the average hyperfine field ${H}_{\mathrm{hf}}(T)$ show a temperature dependence $\frac{[{H}_{\mathrm{hf}}(T)\ensuremath{-}{H}_{\mathrm{hf}}(0)]}{{H}_{\mathrm{hf}}(0)}=\ensuremath{-}{B}_{\frac{3}{2}}{(\frac{T}{{T}_{F}})}^{\frac{3}{2}}\ensuremath{-}{C}_{\frac{5}{2}}{(\frac{T}{{T}_{F}})}^{\frac{5}{2}\

For ${\mathrm{Cd}}_{x}{\mathrm{Fe}}_{3\ensuremath{-}x}{O}_{4}$ and ${\mathrm{Zn}}_{x}{\mathrm{Fe}}_{3\ensuremath{-}x}{O}_{4}$, the conduction-electron concentration has been varied over a wide range without the introduction of $B$-site impurities or defects. Analysis of the $^{57}\mathrm{Fe}$ M\"ossbauer-effect data in terms of the local configurations of ${\mathrm{Zn}}^{2+}$ or ${\mathrm{Cd}}^{2+}$ about a $B$-site Fe has permitted the influence of the conduction electrons on the electrostatic

${\mathrm{Cu}}_{0.5}$${\mathrm{Fe}}_{0.05}$${\mathrm{Cr}}_{2}$${\mathrm{S}}_{4}$ has been studied by M\"ossbauer spectroscopy and x-ray diffraction. The crystal structure is found to be a cubic spinel with the lattice parameter ${a}_{0}$=9.922 A\r{}. The temperature dependence of both the magnetic hyperfine field and magnetization is explained by the N\'eel theory of ferrimagnetism using three exchange integrals: ${J}_{\mathrm{Fe}\mathrm{\ensuremath{-}}\mathrm{Cr}/{k}_{B}=\mathrm{\ensuremath{-}}

${\mathrm{CuCr}}_{0.1}$${\mathrm{Fe}}_{1.9}$${\mathrm{O}}_{4}$ has been studied by M\"ossbauer spectroscopy and x-ray diffraction. The crystal structure is found to be a tetragonal spinel with the lattice parameters ${a}_{0}$=5.843 A\r{} and ${c}_{0}$=8.578 A\r{}. The M\"ossbauer spectra consist of two six-line patterns corresponding to ${\mathrm{Fe}}^{3+}$ at the tetrahedral (A) and octahedral (B) sites. Debye temperatures for A and B sites are found to be 677\ifmmode\pm\else\textpm\fi{}5 and 2

$^{57}\mathrm{Fe}$ M\"ossbauer measurements show that the ratio of the integrated intensities of the $^{57}\mathrm{Fe}$ $A$- and $B$-site M\"ossbauer subspectra is in good agreement with those expected for the cation distribution $({\mathrm{Fe}}^{3+})({\mathrm{Fe}}_{1\ensuremath{-}x}^{3+}{\mathrm{Fe}}^{2+}{\mathrm{Cr}}_{x}){\mathrm{O}}_{4}$, $0\ensuremath{\le}x\ensuremath{\le}0.3$. The magnetic moments are also found to be in good agreement with this cation distribution. The compositional depend

CuFe2O4 has been studied by Mössbauer spectroscopy and X-ray diffraction. The crystal is found to have a tetragonal spinel structure with the lattice constants a0 = (5.805 ± 0.005) Å and c0 = (8.669 ± 0.005) Å. The iron ions are in ferric Fe3+ states. The temperature dependence of the magnetic hyperfine fields at 57Fe nuclei at the tetrahedral (A) and octahedral (b) sites is analyzed by the Néel theory of ferrimagnetism. The intersublattice superexchange interaction is found to be antiferromagne

The changes in the magnetic properties of amorphous ferromagnetic Fe75.4B14.2Si10.4 ribbons have been followed as a function of annealing temperature, TA, by Mossbauer spectroscopy and X-ray diffraction. During structural relaxation before the onset of crystallisation, the magnetic hyperfine field increases steadily with increasing TA while the quadrupole and isomer shifts remain unchanged. The onset of bulk crystallisation is preceded by surface crystallisation in conjunction with which magneti