Magnetic Order and Magneto-Elasticity in the Electronic Excitations of Gd-$i$-MAX

Fuente: arXiv
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Autori principali: Panda, Kartik, Potashnikov, Daniel, Pesach, Asaf, Barbier, Maxime, Eyal, Anna, Ouisse, Thierry, Keren, Amit, Bachar, Nimrod
Natura: Preprint
Pubblicazione: 2024
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author Panda, Kartik
Potashnikov, Daniel
Pesach, Asaf
Barbier, Maxime
Eyal, Anna
Ouisse, Thierry
Keren, Amit
Bachar, Nimrod
author_facet Panda, Kartik
Potashnikov, Daniel
Pesach, Asaf
Barbier, Maxime
Eyal, Anna
Ouisse, Thierry
Keren, Amit
Bachar, Nimrod
contents We report the investigation of electronic collective modes in rare-earth-based magnets (Mo$_{2/3}$RE$_{1/3}$)$_2$AlC (also known as RE-$i$-MAX phases), where RE=Gd, Yb, and Dy, using single crystal samples. A detailed investigation of the Raman spectra of Gd-$i$-MAX samples at low temperatures, with a focus on the phonon behavior in relation to the antiferromagnetic (AFM) phase transition at 26 K is presented. Significant shifts in the central frequencies of several low-frequency phonon modes were observed below 25 K, correlating with the Néel transition. Integrated Raman intensity measurements indicated a reduction in the electronic background below the AFM transition temperature, suggesting the opening of a magnetic gap. Our analysis showed no new phonon modes. Therefore, we do not see any indication of a Brillouin zone folding of phonon mode to the $Γ$-point in our measurement. However, the hardening of all phonon modes at low temperatures points to a strong spin-phonon coupling effect. Using a temperature-dependent model of phonon frequency, we determined the spin-phonon coupling constant $λ$ to be less than 0.1 cm$^{-1}$ for all frequencies, which is of the same order of magnitude as found in other antiferromagnetic materials such as MnF$_{2}$ and FeF$_{2}$ with $T_N=68~K$ and $T_N=78~K$, respectively, but significantly lower than that of $CuO$ with $T_N=213~K$.
format Preprint
id arxiv_https___arxiv_org_abs_2408_02436
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetic Order and Magneto-Elasticity in the Electronic Excitations of Gd-$i$-MAX
Panda, Kartik
Potashnikov, Daniel
Pesach, Asaf
Barbier, Maxime
Eyal, Anna
Ouisse, Thierry
Keren, Amit
Bachar, Nimrod
Strongly Correlated Electrons
We report the investigation of electronic collective modes in rare-earth-based magnets (Mo$_{2/3}$RE$_{1/3}$)$_2$AlC (also known as RE-$i$-MAX phases), where RE=Gd, Yb, and Dy, using single crystal samples. A detailed investigation of the Raman spectra of Gd-$i$-MAX samples at low temperatures, with a focus on the phonon behavior in relation to the antiferromagnetic (AFM) phase transition at 26 K is presented. Significant shifts in the central frequencies of several low-frequency phonon modes were observed below 25 K, correlating with the Néel transition. Integrated Raman intensity measurements indicated a reduction in the electronic background below the AFM transition temperature, suggesting the opening of a magnetic gap. Our analysis showed no new phonon modes. Therefore, we do not see any indication of a Brillouin zone folding of phonon mode to the $Γ$-point in our measurement. However, the hardening of all phonon modes at low temperatures points to a strong spin-phonon coupling effect. Using a temperature-dependent model of phonon frequency, we determined the spin-phonon coupling constant $λ$ to be less than 0.1 cm$^{-1}$ for all frequencies, which is of the same order of magnitude as found in other antiferromagnetic materials such as MnF$_{2}$ and FeF$_{2}$ with $T_N=68~K$ and $T_N=78~K$, respectively, but significantly lower than that of $CuO$ with $T_N=213~K$.
title Magnetic Order and Magneto-Elasticity in the Electronic Excitations of Gd-$i$-MAX
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2408.02436