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S. Khmelevskyi, P. Mohn:
"Magnetostriction in Fe-based alloys and the origin of the Invar anomaly ";
Physical Review B, 69 (2004), 140404-1 - 140404-4.

We show that for Fe-based alloys the spontaneous volume magnetostriction can be calculated from first
principles in good agreement with experiment. Our results are obtained by modeling the paramagnetic state
above the magnetic ordering temperature as a state with disordered local moments. Investigating bcc Fe-Co
and fcc Fe-Pt~Pd! alloys which exhibit large values of the volume magnetostriction in a certain range of
chemical composition and concomitantly an anomalously low thermal expansion coefficient ~Invar effect!, we
find that this behavior is due to changes in the electronic structure induced by the effects of magnetic disorder
leading to reduced local atomic moments in the paramagnetic state. The large values of the spontaneous
volume magnetostriction found in Invar alloys scale with the equally observed large changes in the local
moments.
DOI: 10.1103/PhysRevB.69.140404 PACS number~s!: 75.50.Bb, 65.40.De, 71.15.Mb, 75.80.1q

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