T. J. Burch

Site preference of dilute transition metal solutes in Fe3Si

Abstract Dilute alloys of the type Fe 3− x T x Si (0⩽ x ⩽0.2), with T = V, Cr, Mn, Co, Ta, and W, were studied by means of neutron diffraction. The results indicate that V, Cr and Mn have a clear preference for the Fe site with 8 Fe first neighbors, Co for the Fe site with 4 Fe and 4 Si first neighbors, while only tentative conclusions can be drawn for Ta and W.

Properties of Heusler-type materials Fe2TSi and FeCo2Si

Abstract A number of 3d, 4d and 5d elements are substituted into Fe3Si in an attempt to form Heusler-like alloys. It is found that with the heat treatment followed, only the 3d elements V, Mn and Co form Heusler alloys. Substitution of the other elements produces polyphase materials. For such elements the limits of solubility in Fe3Si are determined. For the Heusler alloys the data on degrees of disorder, hyperfine fields and magnetization are presented. These studies, in addition, test the already known site preferences of the transition metal impurities in Fe3Si at high impurity concentrations.

Temperature dependent splitting of the 59Co hyperfine field in GdCo2

Abstract We have studied the temperature dependence of the 59Co NMR in the magnetically ordered state in GdCo2 between 1.3 K and 335 K. A clearly resolved splitting in the 59Co spectrum is observed to occur at 200 K. This splitting is interpreted as due to a change in easy axis from [100] to a detection which is not a major symmetry axis. Furthermore, a sharp change in the intensity ratio of the two clearly resolved lines in the spectrum occurs at about 300 K.

Hyperfine interactions and structural disorder of Fe3Si1-xAlx alloys

Spin echo, X-ray and magnetization measurements are performed on Fe3Si1-xAlx alloys for 0<x<0.25. The results are analysed by considering near neighbour environments for various sites.

The effect of conductivity on the Eu153 hyperfine interactions in EuTe

The hyperfine interactions of Eu153 in two well characterized samples of EuTe have been measured at liquid helium temperatures by spin‐echo NMR. One of the samples is a conductor and the other one essentially a nonconductor. Our studies indicate that the Eu153 hyperfine interactions are sensitive to the conductivity of the samples. Published magnetization measurements on these samples are used to interpret our NMR results. A tentative identification of the Te123,125 resonances is made.

Electrical resistivity and magnetic susceptibility of Pt1−xCox

Electrical resistivity measurements have been carried out on 4 samples of PtCo with between 0.6 and 5 at.% Co. This resistivity data exhibits a strong temperature dependence in the impurity contribution. The overall temperature and concentration dependent characteristics of the data bear a strong resemblance to features attributed to scattering from localized spin fluctuations. Below the ordering temperatures low field susceptibility experiments show a pronounced deviation from the behavior expected of a ferromagnet for the samples with Co concentration equal to 0.8 and 2 at.%.

Magnetic ordering in PdGd: Electrical resistivity and magnetic susceptibility

We have measured the temperature dependences of the electrical resistivity, ρ (T), and the low field magnetic susceptibility, χ (T), for PdGd containing up to 5 at.% Gd. For alloys containing 2, 3, and 5 at.% Gd, ρ (T) shows a sharp reduction in the spin disorder scattering at the ferromagnetic Curie temperature Tc, obtained from χ (T). Previous electrical resistivity measurements failed to exhibit the effect of magnetic ordering because the high field estimates of Tc used were significantly larger than the values we found. Resistivity data yield estimates of the conduction electron‐local moment exchange interaction to be ∠.003 eV.

Local configuration studies of ferromagnetic Co-Ga alloys using neutron scattering and spin-echo NMR☆

Abstract Neutron scattering and spin-echo NMR experiments are performed on several magnetically ordered Co-Ga, Co2Ga2−xVx and Co2Ga2−xCrx alloys to study the distribution of the magnetic moments and local environments.

Magnetization and neutron diffraction studies on Mn3Si

Bulk magnetization and neutron diffraction measurements on Mn3Si are reported. Preliminary conclusions indicate a complex magnetic structure at low temperatures. The influence of dilute iron substitution on the magnetic behavior of Mn3Si is discussed.

Electrical resistivity of Fe dissolved in PdAg matrix alloys

Abstract The temperature dependence of the resistivities of the system Pd1−xAgx up to x = 0.5, doped with 0.5, 1.0 and 2 at.% Fe has been measured. Clear reduction in the resistivities near the ferromagnetic and spin glass ordering temperatures are observed. The resistance minima observed in some of these alloys are discussed in terms of local s-d effects.