Alloys magnetic structures

Ovchinnikov, V.V. Mossbauer Analysis of the Atomic and Magnetic Structure of Alloys. Cambridge International Science, Cambridge (2004)... 

S.K. Sinha, Magnetic structures and inelastic neutron scattering metals, alloys and compounds 489... 

Predicted (Given Crystallographic Structure) and Measured Magnetic Structures and Atomic Moments for Several Ordered Alloys ... 

One of the most interesting effects is the so-called Invar-effect, which is observed in FeNi alloys. This was noted already 1897 by Guillaume [148], and consists of a vanishing of the thermal expansion coefficient of FeNi steels at Ni concentrations around 35%, the alloy does not expand when heated. In recent years theoretical as well as experimental communities have expressed an increased interest in the problem [149, 150, 151, 152, 153, 154, 155, 156, 157], because of new suggestions of the origin of the Invar effect in the FeNi system related to an observation of noncollinear magnetic structures in the alloy [158]. 

Figure 7.14. Total energy calculations of different magnetic structures for an FeNi alloy with 10% Ni. SWS denotes the Wigner-Seitz radius. The inset shows the q vector of the spin spiral and the moment of the alloy components in the spin spiral structure as functions of volume.

The Fe-Mn alloys (2-8-6-7 at. % Mn) have many similarities to the Fe-Al system [36], with the exception that the conduction-electron spin-density oscillations show a phase variation with concentration corresponding to a change in the Fermi radius and band structure (see Figs. 11.5 and 11.6) [32]. In this case the Mn atoms are contributing to the.magnetic structure. 

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