Antiferromagnetic semiconductor Eu3Sn2P4 with Sn–Sn dimer and crown-wrapped Eu

Abstract

<p>A novel antiferromagnetic semiconductor, Eu3Sn2P4, has been discovered. Single crystals of Eu3Sn2P4 were prepared using the Sn self-flux method. The crystal structure determined by single crystal X-ray diffraction shows that Eu3Sn2P4 crystallizes in the orthorhombic structure with the space group <em>Cmca</em> (Pearson Symbol, <em>oP</em>216). Six Sn–Sn dimers connected by P atoms form a Sn12P24 crown-shaped cluster with a Eu atom located in the center. Magnetization measurements indicate that the system orders antiferromagnetically below a <em>T</em>N ∼14 K at a low field and undergoes a metamagnetic transition at a high field when <em>T</em> < <em>T</em>N. The effective magnetic moment is 7.41(3) <em>μ</em>B per Eu, corresponding to Eu2+. The electric resistivity reveals a non-monotonic temperature dependence with non-metallic behavior below ∼60 K, consistent with the band structure calculations. By fitting the data using the thermally activated resistivity formula, we estimate the energy gap to be ∼0.14 eV. Below <em>T</em>N, the resistivity tends to saturate, suggesting the reduction of charge-spin scattering.</p>