Anisotropic lattice dynamics of FePt L10 thin films

Author(s)

Sebastien Couet, Magorzata Sternik, Bart Laenens, Agata Siegel, K Parlinski, Niki Planckaert, Friedrich Gröstlinger, A Chumakov, Rudolf Rüffer, Bogdan Sepiol, Kristiaan Temst, A Vantomme

Abstract

We employed nuclear inelastic scattering of synchrotron radiation to measure the anisotropy in the phonon density of states of an FePt thin film ordered in the L1(0) phase and compared our results with ab initio calculations. We find a strong anisotropy in the phonon density of states along the a and c axes of the crystal, which induces a difference in the calculated thermodynamic and elastic parameters along these axes. Calculations of surface-related effects show that a strong deviation from the bulk vibrational spectrum is observed for an Fe-terminated surface. We deduce by comparison with our surface sensitive measurement that the FePt(100)-oriented surface is Pt terminated. This contrasts with a recent measurement on FePt nanoparticles, where additional low-energy modes are observed. The findings are expected to be representative of the lattice dynamics of L1(0) intermetallics.

Organisation(s)

Dynamics of Condensed Systems

External organisation(s)

Katholieke Universiteit Leuven, Polish Academy of Sciences (PAS), European Synchrotron Radiation Facility ESRF

Journal

Physical Review B

Volume

82

No. of pages

4

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.82.094109

Publication date

2010

Peer reviewed

Yes

Austrian Fields of Science 2012

103015 Condensed matter

Portal url

https://ucrisportal.univie.ac.at/en/publications/dbe01932-8221-450c-8ba0-4d24715d3970