Eu2Pt7MP4−x (M = Cr, Fe) phosphide platinides, intrinsic heterostructures with a high degree of tunable magnetic anisotropy for spintronics applications

Abstract

Two quaternary phosphide platinides, Eu₂Pt₇CrP_2.80 (I4/mmm, a = 4.0268(3) Å, c = 26.813(3) Å, V = 434.78(8) ų, Z = 2, R₁ = 0.0328, and wR₂ = 0.0785) and Eu₂Pt₇FeP_3.02 (I4/mmm, a = 4.0359(6) Å, c = 26.641(5) Å, V = 433.94(16) ų, Z = 2, R₁ = 0.0276, and wR₂ = 0.0741), were synthesized as single crystals by a high-temperature route using metallic fluxes (Pb or Bi), and their crystal structures were established from single-crystal X-ray diffraction data and confirmed by elemental analysis. The compounds crystallize in the tetragonal system and represent heterostructures built from the alternating layers of AuCu₃- and CaBe₂Ge₂-type fragments. According to DFT calculations, both compounds are metallic. Chemical bonding analysis reveals a pattern of covalent, metallic and ionic interactions within each compound. Magnetic measurements show both compounds to be ferromagnetic with a high degree of magnetic anisotropy and reveal an antiferromagnetic exchange between two magnetic sublattices (europium and chromium or iron), which makes such compounds promising objects for use in spintronics.