Title: Crystal structure and physical properties of Yb₂In and Eu_2–xYb_xIn alloys

Abstract

While binary $R{E}_2\mathrm{In}$, where $RE=\mathrm{rare}\mathrm{earth}$, have been reported a few decades ago, recent investigations revealed intriguing new physical insights. For instance, the discovery of a nearly ideal first-order ferromagnetic transition in ${\mathrm{Eu}}_2\mathrm{In}$ calls for further exploration of structures and properties of $R{E}_2\mathrm{In}$, in particular for the least-documented $RE=\mathrm{Eu}$ and Yb cases. In this work, we investigate ${\mathrm{Eu}}_{2\text{–}x}{\mathrm{Yb}}_x\mathrm{In}$ pseudobinaries with nominal values of $x=0.25$, 0.5, 0.75, 1, 1.5, 2 by powder x-ray diffraction (including as function of temperature from 100 to 375 K for ${\mathrm{Yb}}_2\mathrm{In}$), magnetization (5–300 K), as well as electrical resistivity (5–300 K) and calorimetric (2–150 K) measurements for ${\mathrm{Yb}}_2\mathrm{In}$. Compared to other RE, Yb or Eu always raise challenging questions linked to their valence states. From average atomic volume, Yb is anticipated to be divalent in ${\mathrm{Yb}}_2\mathrm{In}$, at least between 100 and 375 K, which is in line with the absence of $4f$ magnetism. In agreement with x-ray diffraction and magnetization data, the resistivity of ${\mathrm{Yb}}_2\mathrm{In}$ is rather featureless and typical of a metal. Establishing ${\mathrm{Yb}}_2\mathrm{In}$ as a nonmagnetic isostructural reference for ${\mathrm{Eu}}_2\mathrm{In}$ allows one to use its heat capacity to revisit that of the latter, and get experimental insights into the exceptional magnetocaloric effect of the compound with Eu. In particular, we show that a third of the total magnetic entropy ( $S_{\mathrm{m}}\approx 35.6\mathrm{J}\mathrm{mo}{\mathrm{l}}^{–1}{\mathrm{K}}^{–1}$ at $T=100\mathrm{K}$) is concentrated in a 3 K temperature window around the $T_{\mathrm{C}}$ of ${\mathrm{Eu}}_2\mathrm{In}$. Starting from the ferromagnetic compound ${\mathrm{Eu}}_2\mathrm{In}$ $[T_{\mathrm{C}}=55.2\left(5\right)\mathrm{K}]$, we show that Yb substitutions in ${\mathrm{Eu}}_{2\text{–}x}{\mathrm{Yb}}_x\mathrm{In}$ lead to a decrease in both the Curie temperature [ $T_{\mathrm{C}}=41\left(2\right)$ and 32(2) K for $x=0.25$ and 0.5] and magnetic saturation, while weakening the first-order character of the transition as $x$ increases. A significant isothermal entropy change of $5.1\left(4\right)\mathrm{J}\mathrm{mo}{\mathrm{l}}^{–1}{\mathrm{K}}^{–1}$ for $\mathrm{\Delta }B=2\mathrm{T}$ is found at 44 K in ${\mathrm{Eu}}_{1.75}{\mathrm{Yb}}_{0.25}\mathrm{In}$, demonstrating that the giant magnetocaloric effect of ${\mathrm{Eu}}_2\mathrm{In}$ can be tuned to lower temperatures by Yb substitutions.

Authors:

Guillou, F.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8049-4538"

Yibole, H.  ^[1];

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Hamane, R. ^[2]; Hardy, V.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-1076-7972"

Sun, Y. B. ^[3]; Zhao, J. J. ^[3]; Mudryk, Y. ^[4]; Pecharsky, V. K.  ^[4]

• Search DOE PAGES for author "Pecharsky, V. K."
• Search DOE PAGES for ORCID "0000-0001-9503-7567"

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+ Show Author Affiliations

1. Inner Mongolia Normal Univ. (China)
2. Normandie Univ., Caen (France)
3. Baotou Teacher’s College (China)
4. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)

Publication Date:

Mon Oct 05 00:00:00 EDT 2020

Research Org.:

Ames Laboratory (AMES), Ames, IA (United States); Iowa State Univ., Ames, IA (United States)

Sponsoring Org.:

USDOE; Inner Mongolia Normal University; National Natural Science Foundation of China (NSFC); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division

OSTI Identifier:

1688720

Report Number(s):

IS-J-10,342
Journal ID: ISSN 2475-9953; TRN: US2204130

Grant/Contract Number:  

AC02-07CH11358; 2018YJRC002; 2018YJRC003; NJYT-20-A17; 51850410514; 51961033; 11904188

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Materials

Additional Journal Information:

Journal Volume: 4; Journal Issue: 10; Journal ID: ISSN 2475-9953

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY