Showing papers by "W. C. Koehler published in 1965"

DISTRIBUTION OF MAGNETIC MOMENTS IN Pd-3d AND Ni-3d ALLOYS

Abstract: Neutron-scattering and magnetization measurements were made on a series of face-centered cubic $\mathrm{P}\mathrm{d}\ensuremath{-}3d$ and $\mathrm{N}\mathrm{i}\ensuremath{-}3d$ alloys to determine the distribution of magnetic moments in these ferromagnetic binary alloys. The specific alloys studied were: ${\mathrm{Ni}}_{3}$Co, NiCo, ${\mathrm{Pd}}_{3}$Co, PdCo, ${\mathrm{Pd}}_{3}$Fe (ordered and disordered), PdFe, ${\mathrm{Pd}}_{0.93}$${\mathrm{Fe}}_{0.07}$, and ${\mathrm{Pd}}_{0.97}$${\mathrm{Fe}}_{0.03}$. Magnetic moments of about 3.0, 1.8, and 0.6 Bohr magnetons per atom were found for Fe, Co, and Ni, respectively, and these were essentially independent of concentration. The average Pd moment varies with concentration and approaches a maximum of about 0.4 Bohr magnetons per atom in the concentrated alloys.

Magnetic Structures of Metallic Erbium

Abstract: Single-crystal neutron-diffraction data were obtained for metallic erbium at sample temperatures from 42 to 298\ifmmode^\circ\else\textdegree\fi{}K Three distinct regions of long-range magnetic order were observed In the high-temperature region (52-80\ifmmode^\circ\else\textdegree\fi{}K) the ordered moments are confined to the $c$-axis direction and are sinusoidally modulated with a modulation wavelength of $35{C}_{0}$ The amplitude of this modulation saturates at 52\ifmmode^\circ\else\textdegree\fi{}K with ${\ensuremath{\mu}}_{z}(max)=76$ ${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$${\mathrm{Er}}^{3+}$ Below 52\ifmmode^\circ\else\textdegree\fi{}K the basal-plane component of the moment begins to order, and a third-order modulation along the $c$ axis is observed These effects are interpreted on the basis of a squared elliptical spiral with its major axis tilted relative to the crystal $c$ axis However, the structural details in this region are obscured by a temperature variation of the modulation wavelength and by the incommensurability of the modulation and the lattice In the low-temperature region (42-20\ifmmode^\circ\else\textdegree\fi{}K) a ferromagnetic spiral structure is indicated At saturation the ferromagnetic $c$-axis component is 79 ${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$${\mathrm{Er}}^{3+}$ and the spiral basal-plane component is $43{\ensuremath{\mu}}_{B}/{\mathrm{Er}}^{3+}$ The total ordered moment is then the free-ion value of $90{\ensuremath{\mu}}_{B}/{\mathrm{Er}}^{3+}$

Magnetic Structure versus Electron Number for Some Rare-Earth Intermetallic Compounds

Abstract: Neutron diffraction measurements were made on a series of rare‐earth compounds in the Tb(Pd, Ag) and Tb(Ag, In) systems. Most of these compounds exhibit the CsCl type of crystal structure and, for these, magnetic structure determinations were made in order to relate the type of magnetic structure to the number of valence electrons. Two types of antiferromagnetic structures were observed; the (ππ0) type consisting of an antiparallel array of ferromagnetic (110) planes of moments, and the (00π) type with ferromagnetic (001) planes of moments alternating in direction. On the basis of 0, 1, 3, and 3 valence electrons for Pd, Ag, In, and Tb, respectively, the (ππ0) structure is found in the region of 3.5 to 4 valence electrons per unit cell and the (00π) structure in the region of 5 valence electrons per unit cell.