Thermodynamic stability and contributions to the Gibbs free energy of nanocrystalline 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Ni</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mi>Fe</mml:mi></mml:math>

Lohaus, Stefan Haegeli; Johnson, Michel B.; Ahnn, Peter F.; Saunders, Claire; Smith, Harold L.; White, Mary Anne; Fultz, B.

doi:10.1103/physrevmaterials.4.086002

Cited by 11 publications

(3 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data in general were in good agreement with the results of Einstein-model calculations employing the Morse interaction potential [261,262]. A higher population at low frequencies vibrational modes (<15 meV) was also observed in Fe [263,264] and Ni 3 Fe [263][264][265] nanocrystals, nanocrystalline Ni [266][267][268], Fe [267,269], Pd [270], isolated Fe nanoparticles [271], nanoparticles of hematite (α-Fe 2 O 3 ) [272] and Pb [273], nanocrystals of CuFe [274] using inelastic neutron scattering (INS) from which the time-of-flight spectra can directly give the vibrational DOS. The enhancement in the PhDOS at low energies (below 15 meV) was also observed in nanocrystalline Fe [275] and Sn nanoparticles [276] by synchrotron radiation 12 .…”

Section: Modification Of the Phonon Spectrum In Nanoparticlessupporting

confidence: 87%

Phonon softening in nanostructured phonon–mediated superconductors (review)

Prischepa

Kushnir

2023

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Various aspects of phonon spectrum changes in nanostructured phonon-mediated superconductors are considered. It is shown how, with the development of experimental techniques and, accordingly, obtaining new results, the understanding of the influence of the surface and nanoscale on the magnitude of the electron-phonon interaction and the critical temperature Tc changed and deepened. The review is organized as follows. After the Introduction, in the first part we give the quick theoretical background for the description of superconductivity within the framework of various formalisms. In the second part we describe the properties of granular thin films paying attention to the impact of grain sizes and methods of deposition on the Tc value. The role of material parameters is underlined and different aspects of the behavior of granular thin films are discussed. In the third section the impact of external sources of modification of the phonon spectra like noble gases and organic molecules are considered. Problems and progress in this area are discussed. The fourth part is dedicated to the phonon modification and related quantum size effects in nanostructured superconductors. In the fifth part we review the results of direct evidence of phonon softening in nanostructured superconductors and in the sixth section we discuss a possible alternative description of the superconducting properties of nanostructured superconductors related to the concept of metamaterials. In the seventh and eighth parts we review the impact of substrates with lattice mismatched parameters and graphene sheets, respectively, on the modification of the phonon spectrum and enhancement of superconductivity in various superconducting thin films. Finally, in the last ninth section we consider the nonequilibrium superconductivity driven by femtosecond pulses of light, which leads to generation of coherent phonons and to a significant increase in the critical temperature in a number of superconducting materials.

show abstract

Section: Modification Of the Phonon Spectrum In Nanoparticlessupporting

confidence: 87%

Phonon softening in nanostructured phonon–mediated superconductors (review)

Prischepa

Kushnir

2023

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…All the structures contained in the IKUR-PVP-1 data set are subjected to thermodynamic analysis using the harmonic phonon calculations presented in Figure S5. At a given temperature T and constant pressure p , a material under interest reaches equilibrium by minimizing its Gibbs free energy G ( T ) = U ( T ) + p V − T [ S false( T false) ] where U ( T ) is the internal energy and S ( T ) denotes the entropy term (which consists of both vibrational, S vib ( T ), and configurational, S config ( T ), contributions) …”

Section: Resultsmentioning

confidence: 99%

Cation Dynamics as Structure Explorer in Hybrid Perovskites─The Case of MAPbI₃

Drużbicki,

Gila-Herranz,

Marin-Villa

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

Hybrid organic−inorganic perovskites exhibit remarkable potential as cost-effective and high-efficiency materials for photovoltaic applications. Their exceptional chemical tunability opens further routes for optimizing their optical and electronic properties through structural engineering. Nevertheless, the extraordinary softness of the lattice, stemming from its interconnected organic−inorganic composition, unveils formidable challenges in structural characterization. Here, by focusing on the quintessential methylammonium lead triiodide, MAPbI 3 , we combine first-principles modeling with high-resolution neutron scattering data to identify the key stationary points on its shallow potential energy landscape. This combined experimental and computational approach enables us to benchmark the performance of a collection of semilocal exchange−correlation functionals and to track the local distortions of the perovskite framework, hallmarked by the inelastic neutron scattering response of the organic cation. By conducting a thorough examination of structural distortions, we introduce the IKUR-PVP-1 structural data set. This data set contains nine mechanically stable structural models, each manifesting a distinct vibrational response. IKUR-PVP-1 constitutes a valuable resource for assessing thermal behavior in the lowtemperature perovskite phase. In addition, it paves the way for the development of accurate force fields, enabling a comprehensive understanding of the interplay between the structure and dynamics in MAPbI 3 and related hybrid perovskites.

show abstract

“…A key ingredient to guide materials design is Gibbs free energy, which determines the thermodynamic phase stabilities of materials and phase diagrams [1][2][3][4]. For magnetic systems the second-order transition from a magnetically ordered to a paramagnetic state significantly influences the thermodynamic properties [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

New evaluation of the thermodynamics stability for bcc-Fe

Liang

Hou

Zhang

et al. 2022

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The thermodynamic properties for bcc-Fe were predicted by combination of the first-principles calculations, the quasiharmonic approximation, the CALPHAD method and the Weiss molecular field theory. The hybrid method considers the effects of the lattice vibration, electron, intrinsic magnetism and external magnetic fields on the thermodynamic properties at finite temperature. Combined with experimental data, the calculated heat capacity without external magnetic fields was used to verify the validity of the hybrid method. Close to the Fermi level the high electronic DOS leads to a significant electronic contribution to free energy. Near the Curie temperature lattice vibrations dominant the Gibbs free energy. The order of the other three excitation contributions to Gibbs free energy from high to low is: intrinsic magnetism > electron > external magnetic fields. The investigation suggests that all the excitation contributions to Gibbs free energy are not negligible which provides a correct direction for tuning the thermodynamic properties for Fe-based alloy.

show abstract

Thermodynamic stability and contributions to the Gibbs free energy of nanocrystalline Ni3Fe

Cited by 11 publications

References 81 publications

Phonon softening in nanostructured phonon–mediated superconductors (review)

Phonon softening in nanostructured phonon–mediated superconductors (review)

Cation Dynamics as Structure Explorer in Hybrid Perovskites─The Case of MAPbI₃

New evaluation of the thermodynamics stability for bcc-Fe

Contact Info

Product

Resources

About

Thermodynamic stability and contributions to the Gibbs free energy of nanocrystalline Ni3Fe

Cited by 11 publications

References 81 publications

Phonon softening in nanostructured phonon–mediated superconductors (review)

Phonon softening in nanostructured phonon–mediated superconductors (review)

Cation Dynamics as Structure Explorer in Hybrid Perovskites─The Case of MAPbI3

New evaluation of the thermodynamics stability for bcc-Fe

Contact Info

Product

Resources

About

Cation Dynamics as Structure Explorer in Hybrid Perovskites─The Case of MAPbI₃