Theory of Magnetic Phase Transitions

Landau, D. P.

doi:10.1002/9780470022184.hmm110

Cited by 2 publications

(2 citation statements)

References 122 publications

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“…We choose the lattice constants a # and b # as representatives for probing the order of this transition at low temperatures to give rise to the axial distortion of the [FeO 6 ] entity eventually leading to the 5 A g electronic ground state of Fe(II); see also Figure . In Figure we show the power law fitting within the Landau theory to (eq ). …”

Section: Phase Transitionmentioning

confidence: 99%

Screw-Type Motion and Its Impact on Cooperativity in BaNa₂Fe[VO₄]₂

Reuß¹,

Ksenofontov²,

Tapp³

et al. 2018

Inorg. Chem.

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BaNaFe[VO] contains a Jahn-Teller active ion (Fe, 3d, high-spin) in an octahedral coordination. On the basis of a combination of temperature-dependent X-ray diffraction and Mössbauer and Raman spectroscopies, we demonstrate the coupling of lattice dynamics with the electronic ground state of Fe. We identify three lattice modes combined to an effective canted screw- type motion that drives the structural transition around room temperature from the high-temperature ( P3̅) via intermediate phases to the low-temperature phase ( C2/ c). The dynamics of the electronic ground state of Fe(II) are evident from Mössbauer data with signatures of a motion-narrowed doublet above 320 K, a gradual evolution of the E electronic state below 293 K, and finally the signature of the thermodynamically preferred orbitally nondegenerate ground state (A) of Fe(II) below 100 K. The continuous nature of the transition is associated with the temperature-dependent phonon parameters derived from Raman spectroscopy, which point out the presence of strong electron-phonon coupling in this compound. We present a microscopic mechanism and evaluate the collective component leading to the structural phase transition.

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Section: Phase Transitionmentioning

confidence: 99%

Screw-Type Motion and Its Impact on Cooperativity in BaNa₂Fe[VO₄]₂

Reuß¹,

Ksenofontov²,

Tapp³

et al. 2018

Inorg. Chem.

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“…The study of phase transitions in magnetocaloric materials requires that new computational tools able to capture the effect of varying temperature on the shape of magnetization curve be developed [7][8][9][10]. In our opinion a convenient description for this purpose could be the Harrison model [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

The Harrison Model as a Tool to Study Phase Transitions in Magnetocaloric Materials

2018

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Modeling of hysteresis loops close to the Curie point may shed some light on physics of magnetization processes in magnetocaloric materials. In the present paper the model advanced by Harrison is used to describe magnetization curves of La(Fe,Co,Si)13 alloy. Systematic study has revealed that values of some model parameters depend significantly on temperature. The trends of their variations are discussed in the paper.

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Theory of Magnetic Phase Transitions

Cited by 2 publications

References 122 publications

Screw-Type Motion and Its Impact on Cooperativity in BaNa₂Fe[VO₄]₂

Screw-Type Motion and Its Impact on Cooperativity in BaNa₂Fe[VO₄]₂

The Harrison Model as a Tool to Study Phase Transitions in Magnetocaloric Materials

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Theory of Magnetic Phase Transitions

Cited by 2 publications

References 122 publications

Screw-Type Motion and Its Impact on Cooperativity in BaNa2Fe[VO4]2

Screw-Type Motion and Its Impact on Cooperativity in BaNa2Fe[VO4]2

The Harrison Model as a Tool to Study Phase Transitions in Magnetocaloric Materials

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Screw-Type Motion and Its Impact on Cooperativity in BaNa₂Fe[VO₄]₂

Screw-Type Motion and Its Impact on Cooperativity in BaNa₂Fe[VO₄]₂