Valence Instability in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Eu</mi><mrow><msub><mrow><mo>(</mo><mrow><msub><mrow><mi mathvariant="normal">Pd</mi></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></mrow><mrow><msub><mrow><mi mathvariant="normal">Au</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi mathvariant="normal">Si</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>: The Global Phase Diagram

C. U. Segre; M. Croft; J. A. Hodges; V. Murgai; L. C. Gupta; R. D. Parks

doi:10.1103/PhysRevLett.49.1947

Valence Instability in $Eu {({Pd}_{1 - x} {Au}_{x})}_{2} {Si}_{2}$ : The Global Phase Diagram

C. U. Segre, M. Croft, J. A. Hodges, V. Murgai, L. C. Gupta, and R. D. Parks

Phys. Rev. Lett. 49, 1947 – Published 27 December 1982

Abstract

A system has been discovered in which the characteristic energies of a valence instability and a magnetic ordering instability can be brought into parity. This leads to a novel phase diagram where a line of second-order magnetic transitions terminates at a line of first-order valence transitions which, in turn, terminates at a critical point. Microscopic Mössbauer-effect measurements of the order parameters across both magnetic and valence instabilities, along with bulk magnetic susceptibility measurements, are presented.