Epitaxial EuPd2Si2 thin films
307-01 Experimental Condensed Matter Physics
Type(s) of data
Bulk EuPd2Si2 show a temperature-driven valence transisition of europium from ~+2 above 200 K to~+3 below 100 K, which is correlated with a shrinking by approximatly 2 % of the crystal lattice along the two a-axes. Due to this interconnection between lattice and electronic degrees of freedom the influence of strain in epitaxial thin films is particularly interesting. Ambient X-ray diffraction (XRD) confirms an epitaxial relationship of tetragonal EuPd2Si2 on MgO(001) with an out-of plane c-axis orientation for the thin film, whereby the a-axes of both lattices align. XRD at low temperatures reveals a strong coupling of the thin film lattice to the substrate, showing no abrupt compression over the temperature range from 300 to 10 K. Hard X-ray photoelectron spectroscopy at 300 and 20 K reveals a temperature-independent valence of +2.0 for Eu. The evolving biaxial tensile strain upon cooling is suggested to suppress the valence transition. Instead low temperature transport measurements of the resistivity and the Hall effect in a magnetic field up to 5 T point to a film thickness independent phase transition at 16-20 K, indicating magnetic ordering.
|Name||Type of identifier||Funder identifier||Award number||Award title||Award URI|
DFG German Research Fundation
TRR 288 Elastic Tuning and Response of Electronic Quantum Phases of Matter