Crystallographic and magnetic structure of RbCoCl3 · 2 D2O

The crystallographic and magnetic structure of RbCoCl3 · 2 D2O were determined mainly by means of neutron diffraction measurements. Below TN = 2.79 K the magnetic moments are ordered in a canted antiferromagnetic pattern. A meta-magnetic phase transition is observed at unusually small field values (H = 18 Oe at T = 2 K)

Influence of the FM/AFM interface morphology on the exchange coupling in epitaxial Co(001)/fct-Mn(001)

The Co thickness dependence of the exchange interaction between ferromagnetic (FM) fct-Co(001) and antiferromagnetic (AFM) fct-Mn(001) thin layers, epitaxially grown on Cu(001) single crystals, was studied. In the pseudomorphic Co growth regime, oscillations of the coercivity (HC) and the exchange bias (HE) with a Co at. monolayer period are obsd. These oscillations are explained by a biquadratic exchange interaction component at the FM/AFM interface which, in this thickness range, is modulated by the layer-by-layer growth mode of Co on Cu(001). [on SciFinder (R)

Monolayer resolved oscillating hyperfine fields in epitaxial face-centered-tetragonal Co(001) films

Ultrahigh-quality thin fct-Co films grown on Cu(001) were studied by 59Co NMR. The influence of the spin-dependent electron scattering at the interfaces is obsd. for at least four Co at. layers from the interface with monolayer resoln. An oscillatory effect on the Co hyperfine field with a period of several monolayers is measured, corresponding to the oscillating conduction electron polarization. The observation is exclusively possible in this system due to its very narrow resonance lines, corresponding to a virtually perfect Co structure. [on SciFinder (R)

Electric-field gradients in thin face-centered-tetragonal Co films observed by nuclear magnetic resonance

Thin tetragonally strained fcc-Co films grown epitaxially on Cu(001) single crystals have been investigated by 59Co nuclear magnetic resonance (NMR). The ultrahigh structural quality and the homogeneity of the strain result in the direct NMR observation of electric-field gradients, which is unique in thin films. The structural quality and the homogeneity and size of the strain are analyzed by means of the very small NMR linewidths, the hyperfine field anisotropies, and the uniform electric-field gradients. A quantitative agreement with the observed strain is found. The strain, and thus the tetragonal distortion, in the films is found to be surprisingly stable, showing less than 10% strain relief for 80 ML Co films

Formation of nonmagnetic c-Fe_{1-x}Si in antiferromagnetically coupled epitaxial Fe/Si/Fe

Low-energy electron diffraction, Auger electron spectroscopy, and conversion electron Mössbauer spectroscopy have been applied to study antiferromagnetically exchange-coupled epitaxial Fe/Si/Fe(100). It is shown that a bcc-like (100) structure is maintained throughout the layers after a recrystallization of the spacer layer by Fe/Si interdiffusion. Direct experimental evidence is presented that c-Fe1-xSi (

Specific heat of nearly-one-dimensional tetramethyl ammonium manganese trichloride (TMMC) and tetramethyl ammonium cadmium trichloride (TMCC)

The specific heat of tetramethyl ammonium manganese trichloride and its cadmium isomorph is measured for 2&lt;T&lt;52 K. The temperature dependence of the lattice specific heat of the cadmium compound could be fitted with an expression based upon a pseudoelastic approach of the lattice vibrations in this low-dimensional system. Application of this approach to the manganese compound yields a magnetic contribution which fits the overall behavior of a one-dimensional Heisenberg model with an intrachain interaction of Jk=-6.70.5 K. Inspection of the low-temperature region yields a satisfactory agreement with the expression Cm=1.1|kTJ|+0.5|kTJ|2-0.13|kTJ|3, predicted by recent calculations.</p

Specific heat of nearly-one-dimensional tetramethyl ammonium manganese trichloride (TMMC) and tetramethyl ammonium cadmium trichloride (TMCC)

The specific heat of tetramethyl ammonium manganese trichloride and its cadmium isomorph is measured for 2&lt;T&lt;52 K. The temperature dependence of the lattice specific heat of the cadmium compound could be fitted with an expression based upon a pseudoelastic approach of the lattice vibrations in this low-dimensional system. Application of this approach to the manganese compound yields a magnetic contribution which fits the overall behavior of a one-dimensional Heisenberg model with an intrachain interaction of Jk=-6.70.5 K. Inspection of the low-temperature region yields a satisfactory agreement with the expression Cm=1.1|kTJ|+0.5|kTJ|2-0.13|kTJ|3, predicted by recent calculations.</p

Analysis of scattering lengths in Co/Cu/Co and Co/Cu/Co/Cu spin-valves using a Ru barrier

We use uncoupled Co/Cu/Co and Co/Cu/Co/Cu spin-valve structures with a Ru barrier shifted through the top Co and Cu layer, respectively, to measure the longest of the electron mean free paths in Co and Cu as originally suggested by Parkin. From semiclassical transport calculations and careful analysis of the magnetoresistance data we conclude that the exponential behavior of ¿G is uniquely related to the longest of the Co and Cu mean free paths under the condition of effective spin-dependent filtering at the interfaces or in the bulk of the Co. In this regime we have compared ¿long in Co and Cu with bulk conductivities (~¿short+¿long), yielding no strong evidence for bulk spin-dependent scattering in Co

Specific heat of ZnCoSe semimagnetic semiconductor

The magnetic specific heat of ZnCoSe data are reported in the temperature range 1.5 &lt;T &lt;50 K and magnetic field B &lt;3 T. The experimental data are interpreted in the Extended Nearest Neighbour Pair Approximation taking into account short and long ranged d-d exchange interaction