Paramagnetic fluctuations of the magnetocaloric compound MnFe4Si3

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10496694" target="_blank" >RIV/00216208:11320/25:10496694 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=tu6KXEjNmI" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=tu6KXEjNmI</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevB.111.054424" target="_blank" >10.1103/PhysRevB.111.054424</a>

Result language
angličtina
Original language name
Paramagnetic fluctuations of the magnetocaloric compound MnFe4Si3
Original language description
An inelastic neutron scattering technique is employed to investigate the paramagnetic spin dynamics in a single-crystalline sample of the magnetocaloric compound MnFe4Si3. In the investigated temperature range, 1.033xTC to 1.5xTC, where TC is the Curie temperature, the spin fluctuations are well described by the ferromagnetic Heisenberg model predictions. Apart from the Heisenberg exchange, additional pseudodipolar interactions manifest through a finite long-wavelength relaxation rate that vanishes at the transition temperature (TC=305 K). Based on the characteristic extent of spin fluctuations in wave-vector and energy space, we determine that the nature of magnetism in MnFe4Si3 is localized above room temperature. This contrasts with the most celebrated Mn- and Fe-based magnetocaloric materials that are considered as itinerant magnets. The field dependence of the paramagnetic spectra shows a strong suppression of the quasielastic excitations, while a field-induced spin-wave mode appears at finite-energy transfers for a magnetic field of 2 T. This modification of the spectra suggests a decrease of magnetic entropy with applied magnetic field that finds echo in the magnetocaloric properties of the system.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Project
<a href="/en/project/GM21-24965M" target="_blank" >GM21-24965M: Magnetoelastic Materials beyond Born-Oppenheimer Approximation</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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