Antiferromagnetism with divalent Eu in EuNi${}_5$As${}_3$

Abstract

We have successfully synthesized single crystals of EuNi${}_5$As${}_3$ using a flux method and we present a comprehensive study of the physical properties using magnetic susceptibility, specific heat, electrical resistivity, thermoelectric power and x-ray absorption spectroscopy (XAS) measurements. EuNi${}_5$As${}_3$ undergoes two close antiferromagnetic transitions at respective temperatures of $T_{N1}$ = 7.2 K and $T_{N2}$ = 6.4 K, which are associated with the Eu${}^{2+}$ moments. Both transitions are suppressed upon applying a field and we map the temperature-field phase diagrams for fields applied parallel and perpendicular to the easy $a$ axis. XAS measurements reveal that the Eu is strongly divalent, with very little temperature dependence, indicating the localized Eu${}^{2+}$ nature of EuNi${}_5$As${}_3$, with a lack of evidence for heavy fermion behavior.

9 pages, 11 figures