Heat capacity and thermal conductivity of CdCr2Se4 ferromagnet: Magnetic field dependence, experiment and calculations

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388980%3A_____%2F23%3A00573167" target="_blank" >RIV/61388980:_____/23:00573167 - isvavai.cz</a>

Alternative codes found

RIV/68378271:_____/23:00570401 RIV/00216275:25310/23:39920229

Result on the web

<a href="https://doi.org/10.1016/j.jpcs.2022.111139" target="_blank" >https://doi.org/10.1016/j.jpcs.2022.111139</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jpcs.2022.111139" target="_blank" >10.1016/j.jpcs.2022.111139</a>

Result language

angličtina

Original language name

Heat capacity and thermal conductivity of CdCr2Se4 ferromagnet: Magnetic field dependence, experiment and calculations

Original language description

The low-temperature specific heat capacity and thermal conductivity under magnetic field 0-13 T is investigated on polycrystalline sample of the ferromagnetic insulator CdCr2Se4, possessing spinel structure with magnetic Cr3+ ions in the octahedrally coordinated sites. The phonon (lattice) and magnon contributions are separated by their characteristic temperature dependencies and by quenching of the magnon component under high magnetic fields in the isothermal measurements. The results are analyzed with respect to formulas for model systems and confronted with ab-initio calculations of phonon and magnon spectra. The theoretical formula for the fieldinduced quenching of magnon heat capacity is well reproduced, but there are two kinds of deviations from expected behavior deserving attention: (1) Heat capacity at low fields is by several percent lower than expected and approaches the theoretical curve only above0.5 T. We propose that the zero-field magnon heat capacity is diminished by a presence of magnetic domain walls and the expected field dependence is restored when magnetic field converts the sample into a single domain state. (2) The suppression of magnon heat capacity under high magnetic field is incomplete. While the data follow well the theoretical line for given temperature as regards the curvature, the final saturation seems to tend several percent above the expected value for lattice heat capacity. We propose that this behavior is related to the phonon-magnon coupling arising due to Zeeman gap in the magnon spectra and subsequent formation of intersection points with the phonon spectra. The thermal conductivity has shown substantial deviations with respect to model predictions as concerns temperature dependence of the phonon contribution and suppression of the magnon contribution in markedly lower magnetic fields than predicted by the model. We ascribe this discrepancy to a complex character of the intergrain heat transfer.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10402 - Inorganic and nuclear chemistry

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

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

Name of the periodical

Journal of Physics and Chemistry of Solids

ISSN

0022-3697

e-ISSN

1879-2553

Volume of the periodical

174

Issue of the periodical within the volume

MAR

Country of publishing house

GB - UNITED KINGDOM

Number of pages

11

Pages from-to

111139

UT code for WoS article

000899354300006

EID of the result in the Scopus database

2-s2.0-85143851152