Publication Date

10-5-2020

Department

Ames Laboratory; Materials Science and Engineering

Campus Units

Materials Science and Engineering, Ames Laboratory

OSTI ID+

1688720

Report Number

IS-J 10342

DOI

10.1103/PhysRevMaterials.4.104402

Journal Title

Physical Review Materials

Volume Number

4

Issue Number

10

First Page

104402

Abstract

While binary RE2In, where RE = rare 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 Eu2In calls for further exploration of structures and properties of RE2In, in particular for the least-documented RE = Eu and Yb cases. Here, we investigate Eu2-xYbxIn 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 Yb2In), magnetization (5-300 K), as well as electrical resistivity (5-300 K) and calorimetric (2150 K) measurements for Yb2In. 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 Yb2In, 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 Yb2In is rather featureless and typical of a metal. Establishing Yb2In as a nonmagnetic isostructural reference for Eu2In 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-m approximate to 35.6 J mol(-1) K-1 at T = 100 K) is concentrated in a 3 K temperature window around the T-C of Eu2In. Starting from the ferromagnetic compound Eu2In [T-C = 55.2(5) K], we show that Yb substitutions in Eu2-xYbxIn lead to a decrease in both the Curie temperature [T-C = 41(2) 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(4) J mol(-1) K-1 for Delta B = 2 T is found at 44 K in Eu1.75Yb0.25In, demonstrating that the giant magnetocaloric effect of Eu2In can be tuned to lower temperatures by Yb substitutions.

DOE Contract Number(s)

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

Language

en

Department of Energy Subject Categories

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

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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