Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in γ − Fe nanoparticles

Autor: Haraldur P. Gunnlaugsson, Kristiaan Temst, V. Joly, Enric Menéndez, Ulrich Wahl, André Vantomme, Ian Vickridge, Felipe Kremer, D. Banerjee, A. R. G. Costa, J. von Bardeleben, J. G. Correia, Maarten Trekels, Joke Hadermann, Gertjan Lippertz, L. M. C. Pereira, J. P. Araújo, T. A. L. Lima, V. Augustyns, M. J. Van Bael, K. van Stiphout
Přispěvatelé: Department of Metalurgy, Engineering School, Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier (UM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), ICAT, Faculdade de Ciencias da Universidade de Lisboa, European Synchrotron Radiation Facility (ESRF), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Couches nanométriques : formation, interfaces, défauts (INSP-E5), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, Australian National University (ANU)
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Physical Review B : Condensed matter and materials physics
Physical Review B : Condensed matter and materials physics, American Physical Society, 2017, 96 (17), pp.174410 ⟨10.1103/PhysRevB.96.174410⟩
Physical Review B
Physical review B
Physical Review B: Condensed Matter and Materials Physics (1998-2015)
Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2017, 96 (17), pp.174410. ⟨10.1103/PhysRevB.96.174410⟩
Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2017, 96 (17), pp.174410. ⟨10.1103/PhysRevB.96.174410⟩
ISSN: 0163-1829
1095-3795
2469-9969
1098-0121
1550-235X
Popis: $\ensuremath{\gamma}\text{\ensuremath{-}}\mathrm{Fe}$ and related alloys are model systems of the coupling between structure and magnetism in solids. Since different electronic states (with different volumes and magnetic ordering states) are closely spaced in energy, small perturbations can alter which one is the actual ground state. Here, we demonstrate that the ferromagnetic state of $\ensuremath{\gamma}\text{\ensuremath{-}}\mathrm{Fe}$ nanoparticles is associated with a tetragonal distortion of the fcc structure. Combining a wide range of complementary experimental techniques, including low-temperature M\"ossbauer spectroscopy, advanced transmission electron microscopy, and synchrotron radiation techniques, we unambiguously identify the tetragonally distorted ferromagnetic ground state, with lattice parameters $a=3.76(2)\phantom{\rule{4pt}{0ex}}\AA{}$ and $c=3.50(2)\phantom{\rule{4pt}{0ex}}\AA{}$, and a magnetic moment of 2.45(5) ${\ensuremath{\mu}}_{B}$ per Fe atom. Our findings indicate that the ferromagnetic order in nanostructured $\ensuremath{\gamma}\text{\ensuremath{-}}\mathrm{Fe}$ is generally associated with a tetragonal distortion. This observation motivates a theoretical reassessment of the electronic structure of $\ensuremath{\gamma}\text{\ensuremath{-}}\mathrm{Fe}$ taking tetragonal distortion into account.
Databáze: OpenAIRE
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