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Muscas G, Johansson R, George S, Ahlberg M, Arvanitis D, Ahuja R, Scheicher RH, Jönsson PE. Unveiling the local structure of the amorphous metal [Formula: see text] combining first-principles-based simulations and modelling of EXAFS spectra. Sci Rep 2023; 13:4983. [PMID: 36973288 PMCID: PMC10042867 DOI: 10.1038/s41598-023-32051-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Amorphous alloys exhibit useful properties such as the excellent soft magnetic behaviour of Fe-based metallic glasses. The detailed structure of amorphous [Formula: see text] with x = 0.07, 0.10, and 0.20 is in this work explored through a synergetic combination of atomistic simulations and experimental characterisation. Thin-film samples were investigated using X-ray diffraction and extended X-ray absorption fine structure (EXAFS), while the corresponding atomic structures were simulated using an efficient first-principles-based method called stochastic quenching (SQ). The simulated local atomic arrangements are investigated by constructing the radial- and angular-distribution functions, as well as by Voronoi tesselation. The radial distribution functions are then used to construct a model to fit simultaneously the experimental EXAFS data of multiple samples with different compositions, creating a simple yet accurate description of the atomic structures valid for any composition in the range x = 0.07 to 0.20, using a minimal number of free parameters. This approach significantly improves the accuracy of the fitted parameters and allows us to relate the compositional dependence of the amorphous structures with the magnetic properties. The proposed EXAFS fitting process can be generalised to other amorphous systems, contributing to the understanding of structure-property relationships and the development of amorphous alloys with tailored functional properties.
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Affiliation(s)
- Giuseppe Muscas
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
- Department of Physics, University of Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 Km 0.700, 09042 Monserrato, CA Italy
| | - Robert Johansson
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
- Present Address: Uppsala Clinical Research Center, Uppsala University Hospital, Box 6363, 751 35 Uppsala, Sweden
| | - Sebastian George
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Martina Ahlberg
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
- Department of Physics, University of Gothenburg, Fysikgränd 3, 412 96 Gothenburg, Sweden
| | - Dimitri Arvanitis
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Rajeev Ahuja
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
- Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 India
| | - Ralph H. Scheicher
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Petra E. Jönsson
- Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
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Rojas O, de Souza SM, Torrico J, Veríssimo LM, Pereira MSS, Lyra ML. Low-temperature pseudo-phase-transition in an extended Hubbard diamond chain. Phys Rev E 2021; 103:042123. [PMID: 34006009 DOI: 10.1103/physreve.103.042123] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/25/2021] [Indexed: 11/07/2022]
Abstract
We consider the extended Hubbard diamond chain with an arbitrary number of particles driven by chemical potential. The interaction between dimer diamond chain and nodal couplings is considered in the atomic limit (no hopping), whereas the dimer interaction includes the hopping term. We demonstrate that this model exhibits a pseudo-transition effect in the low-temperature regime. Here, we explore the pseudo-transition rigorously by analyzing several physical quantities. The internal energy and entropy depict sudden, although continuous, jumps which closely resembles discontinuous or first-order phase-transition. At the same time, the correlation length and specific heat exhibit astonishing strong sharp peaks quite similar to a second-order phase-transition. We associate the ascending and descending parts of the peak with power-law "pseudo-critical" exponents. We determine the pseudo-critical exponents in the temperature range where these peaks are developed, namely, ν=1 for the correlation length and α=3 for the specific heat. We also study the behavior of the electron density and isothermal compressibility around the pseudo-critical temperature.
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Affiliation(s)
- Onofre Rojas
- Departamento de Física, Universidade Federal de Lavras, 37200-900 Lavras, Minas Gerais, Brazil
| | - S M de Souza
- Departamento de Física, Universidade Federal de Lavras, 37200-900 Lavras, Minas Gerais, Brazil
| | - Jordana Torrico
- Departamento de Física, Universidade Federal de Minas Gerais, Caixa Postale 702, 30123-970 Belo Horizonte, Minas Gerais, Brazil
| | - L M Veríssimo
- Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, Alagoas, Brazil
| | - M S S Pereira
- Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, Alagoas, Brazil
| | - M L Lyra
- Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, Alagoas, Brazil
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Webb TA, Ryan DH. A TDPAC study of static and dynamic magnetic behaviour. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:306001. [PMID: 23819993 DOI: 10.1088/0953-8984/25/30/306001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The a-FexHf100-x system is used to explore the application of TDPAC (the time differential perturbed γ-γ angular correlation technique) to non-trivial anisotropic magnetic relaxation. The effect of fluctuations in this system is primarily to cause a decay of the zero-frequency component, which is characterized by the phenomenological decay rate λ. The zero-field magnetic phase diagram, constructed from both static and dynamic features of the data, and the temperature dependence of λ are both fully consistent with the physics of partial bond frustration. The results demonstrate that the magnetic fluctuations are meaningfully characterized by simple spectrum features, and are not obscured by large static fields or severe disorder.
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Affiliation(s)
- T A Webb
- Physics Department and Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, QC, H3A 2T8, Canada.
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Rojas O, de Souza SM, Ananikian NS. Geometrical frustration of an extended Hubbard diamond chain in the quasiatomic limit. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:061123. [PMID: 23005067 DOI: 10.1103/physreve.85.061123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Indexed: 06/01/2023]
Abstract
We study the geometrical frustration of an extended Hubbard model on a diamond chain, where vertical lines correspond to the hopping and repulsive Coulomb interaction terms between sites while the remaining lines represent only the Coulomb repulsion term. The phase diagrams at zero temperature show quite curious phases: five types of frustrated states and four types of nonfrustrated states, ordered antiferromagnetically. Although a decoration transformation was derived for spin-coupling systems, this approach can be applied to electron-coupling systems. Thus the extended Hubbard model can be mapped onto another effective extended Hubbard model in the atomic limit with additional three- and four-body couplings. This effective model is solved exactly using the transfer-matrix method. In addition, using the exact solution of this model, we discuss several thermodynamic properties away from the half-filled band, such as chemical potential behavior, electronic density, and entropy, for which we study geometrical frustration. Consequently, we investigate the specific heat as well.
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Affiliation(s)
- Onofre Rojas
- Departamento de Ciencias Exatas, Universidade Federal de Lavras, CP 3037, 37200-000 Lavras-MG, Brazil
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