Synthesis, crystal structure, and physical properties of the Eu(II)-based selenide semiconductor: EuHfSe3

Black needle-shaped crystals of a novel Eu(II)-containing chalcogenide semiconductor, EuHfSe3, have been synthesized at high temperatures using sealed-tube solid-state reaction techniques. Single crystal X-ray diffraction data (XRD) was used to characterize its structure as forming in the orthorhombic space group Pnma (a = 8.887(1) & Aring;, b = 3.9300(4) & Aring;, c = 14.3827(14) & Aring;, and Z = 4) with the NH4CdCl3 structure type. The extended structure is comprised of [HfSe3](2-) chains which are charge balanced by Eu(II) cations. Eu-151 M & ouml;ssbauer spectroscopic measurements were consistent with the coordination of only Eu(ii) cations in bicapped trigonal prisms of EuSe8. The latter polyhedra are condensed via face-sharing into corrugated [EuSe2Se2/2Se4/4] layers, yielding a magnetic substructure with Eu-Eu distances of similar to 3.93 & Aring; and a longer similar to 4.91 & Aring;. This structural feature of the NH4CdCl3-type structure has been probed for its impact on the magnetic and thermodynamic properties. Magnetic susceptibility and heat capacity measurements uncover two magnetic transitions at T-N1 approximate to 8 K, with glassy character, and at T-N1 approximate to 4 K implying a complex canted antiferromagnetic or ferrimagnetic ground state.