Pressure Dependence of the Second-Order Valence Phase Transition in Eu 2 Al 15 Pt 6 and the Solid Solutions Eu 2 Al 15 (Pt 5/6 T 1/6 ) 6 ( T = Pd, Ir, Au)
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Eu 2 Al 15 Pt 6, synthesized by arc-melting, was shown to exhibit a second-order valence phase transition around 45 K, where the divalent Eu atoms get trivalent below the transition temperature T trans . Substitution of Al by Ga in the solid solution Eu 2 (Al 1– x Ga x ) 15 Pt 6 leads to the vanishing of the valence phase transition at low values of x, while substitution on the Pt position, according to Eu 2 Al 15 (Pt 5/6 T 1/6 ) 6 with T = Pd, Ir, or Au, leads to shifts of the transition temperatures. These substitutions can be considered to superimpose either chemical or electronic pressure, leading to the question of whether the application of physical pressure also has an influence on the valence change. Pressure-dependent magnetic susceptibility measurements have been conducted on Eu 2 Al 15 Pt 6 and the three solid solutions Eu 2 Al 15 (Pt 5/6 T 1/6 ) 6 with T = Pd, Ir, and Au. In line with the expectations, the valence phase transitions under pressure occur at significantly higher temperatures, e.g., T trans (Eu 2 Al 15 Pt 6 @1.0 GPa) = 147(1) K, compared to ∼45 K at ambient pressure. Eu 2 Al 15 (Pt 5/6 Au 1/6 ) 6 does not exhibit a transition at ambient pressure, but interestingly, already at small pressures, the typical anomaly of a valence phase transition is observed in the susceptibility data.
Source: Chemistry of Materials
Institutions: University of Münster, Saarland University
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G4156576272, G5878385263, G72572109
OpenAlex ID: W4417136403