Investigations of the Co-Pt alloy phase diagram with neutron diffuse scattering, inverse cluster variation method and Monte Carlo simulations
| Autor: | Guy Schmerber, Frédéric Fossard, Hiroshi Numakura, J. R. Stewart, Juan M Sanchez, Katsushi Tanaka, V. Pierron-Bohnes, Mathieu Fèvre, Y. Le Bouar, Jean-Sébastien Mérot |
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| Přispěvatelé: | LEM, UMR 104, CNRS-ONERA, Université Paris-Saclay (Laboratoire d'étude des microstructures), ONERA-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), American University of Sharjah, Institut Laue-Langevin (ILL), ILL, ISIS Facility, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Kobe University, Osaka Prefecture University, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Co-Pt alloy
Materials science Ab initio Phase Diagram Inverse Diffuse Neutron Scattering 02 engineering and technology Diffusion diffuse de neutrons 01 natural sciences Paramagnetism Condensed Matter::Materials Science [SPI]Engineering Sciences [physics] Ab initio quantum chemistry methods 0103 physical sciences Simulations Monte Carlo [CHIM]Chemical Sciences Alliage Co-Pt 010306 general physics Diagramme de Phase [PHYS]Physics [physics] Magnetic moment Condensed matter physics Scattering Transition temperature Order (ring theory) 021001 nanoscience & nanotechnology Monte Carlo Simulations 0210 nano-technology |
| Zdroj: | Physical Review B Physical Review B, American Physical Society, 2020, 102 (13), ⟨10.1103/PhysRevB.102.134114⟩ |
| ISSN: | 2469-9950 2469-9969 |
| DOI: | 10.1103/PhysRevB.102.134114⟩ |
| Popis: | The short-range order in a CoPt alloy was determined at 1203 and 1423 K using neutron diffuse scattering measurements. The effective pair interactions provided by data analysis reproduce well the experimental order-disorder transition temperature in Monte Carlo simulations. They complete previous results reported for the Co-Pt system and are compared to those obtained within tight-binding and ab initio formalisms. Our results show that the important dependence of the nearest-neighbor pair interactions with composition is not related to the sample magnetic state at the measured temperatures. Interactions measured in the paramagnetic domain for the CoPt alloy behave like those in the ferromagnetic domain for the ${\mathrm{Co}}_{3}\mathrm{Pt}$ and ${\mathrm{Co}}_{0.65}{\mathrm{Pt}}_{0.35}$ alloys. The effective pair interactions related to the tight-binding Ising model provide a relatively good description of the CoPt alloy thermodynamics close to the ordering temperature (short-range order and temperature of phase transformation), even if they strongly differ from those measured in this study. The average magnetic moment of Co atoms at high temperatures was determined from the analysis of the intensity contribution that is not dependent on the scattering vector. The obtained value is very close to the moment measured at room temperature or determined from ab initio calculations. This confirms the Curie-Weiss behavior of the CoPt alloy. Finally, transmission electron microscope observations carried out on samples annealed for about 30 days confirmed that the order-disorder transition takes place in the 830--843 K temperature interval at the ${\mathrm{Co}}_{3}\mathrm{Pt}$ composition. |
| Databáze: | OpenAIRE |
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