<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Eu</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"

We synthesized a high-quality sample of the boride Eu4Pd(29+x)B8 (x = 0.76) and studied its structural and physical properties. Its tetragonal structure was solved by direct methods and confirmed to belong to the Eu4Pd29B8 type. All studied physical properties indicate a valence fluctuating Eu state, with a valence decreasing continuously from about 2.9 at 5 K to 2.7 at 300 K. Maxima in the T dependence of the susceptibility and thermopower at around 135 K and 120 K, respectively, indicate a valence fluctuation energy scale on the order of 300 K. Analysis of the magnetic susceptibility evidences some inconsistencies when using the ionic interconfigurational fluctuation (ICF) model, thus suggesting a stronger relevance of hybridization between 4f and valence electrons compared to standard valence-fluctuating Eu systems.

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“…(emu mol −1 ). E ex and T sf are in the range of typically reported for valence fluctuating Eu-containing systems [42,[47][48][49][50].…”

Section: Magnetic Susceptibilitymentioning

confidence: 52%

Valence fluctuations of europium in the boride Eu₄Pd_29+xB₈

Gumeniuk

Schnelle

Ahmida

et al. 2016

J. Phys.: Condens. Matter

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“…Because the ionic radius of divalent Eu 2+ is substantially larger than trivalent Eu 3+ , the observed smaller unit-cell volume of the FZ-grown crystal ͑compared to those grown from an In flux͒ is consistent with a larger fraction of the trivalent nonmagnetic configuration Eu 3+ . 17 The reduced fraction of magnetic Eu 2+ ions may explain the lack of any magnetic transition at T Ͼ 2 K both in polycrystals and in the FZgrown crystal studied. Instead, spin fluctuations are observed for low temperatures, which can also give rise to Kondo-like resistance anomalies.…”

Section: Discussionmentioning

confidence: 93%

“…This behavior reflects the well-known valence fluctuations of EuCu 2 Si 2 , 3,4,16 which has been observed for other Eu-containing compounds too. 17 In particular, one expects a Curie-Weiss law of the magnetic susceptibility if the magnetism is governed by a stable magnetic moment associated with a stable Eu valence state. In contrast, the nonlinear temperature dependence of the magnetic susceptibility observed in a variety of materials was straightforwardly attributed to valence fluctuations of the rare-earth ion.…”

Section: Static Magnetizationmentioning

confidence: 99%

Interplay between Kondo-like behavior and short-range antiferromagnetism inEuCu2Si2single crystals

et al. 2008

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The static and dynamic magnetic properties, electrical resistivity, specific heat, and magnetoresistance have been studied in EuCu 2 Si 2 single crystals grown by a floating zone method. The magnetic susceptibility exhibits a considerable anisotropy and a steep rise below 10 K for external fields parallel to the c axis but with no evident magnetic ordering in the temperature range of 2-350 K. The data imply a gradual change in the Eu valence as a function of temperature. Electron spin resonance ͑ESR͒ measurements reveal a sizeable fraction of stable Eu 2+ magnetic moments that interact with conduction electrons and develop quasistatic antiferromagnetic correlations on the ESR timescale. The electrical resistivity and specific heat demonstrate the presence of spin fluctuations and Kondo-like behavior, which apparently competes with the antiferromagnetic order. The analysis of experimental data enables to conclude that the remarkable diversity of the physical properties of EuCu 2 Si 2 results from the variation of lattice parameters as well as of local crystal chemistry as a consequence of the particular preparation route employed for the growth of single crystals and polycrystals.

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“…This behavior reflects the well-known valence fluctuations in this compound [3,4], which was also observed for other Eu-containing compounds [14]. The diversity in the magnetic properties of single crystals from different preparation routes is assumed to result from small differences in composition, lattice parameters and chemical disorder, which are characteristic for the class of RT 2 Si 2 intermetallics.…”

Section: Magnetic and Electronic Transport Propertiesmentioning

confidence: 76%