Paramagnetic fluctuations of the magnetocaloric compound MnFe4Si3

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

Paramagnetic fluctuations of the magnetocaloric compound MnFe4Si3

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Paramagnetic fluctuations of the magnetocaloric compound MnFe4Si3

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

<a href="/cs/project/GM21-24965M" target="_blank" >GM21-24965M: Magnetoelastické materiály za hranicí Born-Oppenheimerovy aproximace</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review B

ISSN

2469-9950

e-ISSN

2469-9969

Svazek periodika

111

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

10

Strana od-do

054424

Kód UT WoS článku

001459360600013

EID výsledku v databázi Scopus

2-s2.0-85218335872