Abstract
LONDON Royal Society, March 1. A. J. BBADLEY and J. W. RODGEBS: The crystal structure of the Heusler alloys. In an investigation of the ferromagnetic alloys of copper, manganese and aluminium, an alloy was found which showed an almost complete change of crystal structure due to heat treatment. Drillings of this alloy, which had been annealed at 500° for several hours and cooled slowly to room temperature, were found to have the & copper aluminium (CujAl4) type of structure. The alloy is non-magnetic, but on quenching from 800° C. it becomes strongly ferromagnetic. The structure is now entirely body-centred cubic, with a face-centred superlattice. On comparing X-ray powder photographs of the same specimen made with radiations from iron, copper and zinc anticathodes, it was found that the relative intensities of the weaker reflections varied with the wave-length of the radiation. This made it possible to distinguish the manganese atoms from the copper atoms. C. SYKES and H. EVANS: Some peculiarities in the physical properties of iron-aluminium alloys. An account is given of measurements of the resistivity of alloys of iron and aluminium containing 11-16 per cent aluminium by weight. Resistivity at room temperature depends on the rate of cooling of the specimens from a temperature of the order of 600° C. Alloys in this range consist of a single solid solution at all temperatures concerned. It is concluded, therefore, that rearrangement of atoms takes place in the alloys under slow cooling conditions, and the more regular arrangement so produced leads to a decrease in resistance. Experimental results suggest that the rearrangement of atoms in the space-lattice takes place over a considerable range of temperatures even under conditions of very slow cooling.
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Societies and Academies. Nature 133, 390–392 (1934). https://doi.org/10.1038/133390a0
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DOI: https://doi.org/10.1038/133390a0