Structural and physical properties of SrMn2As2

SrMn2As2 single crystals were grown by the Sn flux method. Structural features of these crystals were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD results show that the single crystal has a rhombohedral structure and grows along the c-axis direction. The microstructure and layered structural features of this material have been examined by SEM and high-resolution TEM observations. The measurements of in-plane resistivity as a function of temperature demonstrate that SrMn2As2 undergoes a phase transition of semiconductor-insulator at a low temperature; the active energies are estimated to be Delta = 0.64 and 0.29 eV for two distinct regions. Magnetic measurements show a clear antiferromagnetic (AFM) transition at about T-N= 125 K. Therefore, the SrMn2As2 material is an AFM insulator at low temperatures and could be a potential parent compound for superconductors. (C) 2010 Elsevier Ltd. All rights reserved.