Crystal structure and magnetic properties of 6 H -SrMnO 3

摘要: The 6$H$-SrMnO${}_{3}$ polymorph was prepared using a high-pressure and high-temperature technique at 6 GPa 1773 K. Its crystal structure refined synchrotron x-ray powder diffraction data (space group $P$6${}_{3}$/mmc (no. 194), $Z$ $=$ 6, $a$ 5.42892(1) \AA{}, $c$ 13.40252(3) \AA{}). Magnetic transport properties of were investigated direct current magnetization, specific heat, resistivity measurements. antiferromagnetic N\'eel temperature ${T}_{\mathrm{N}}$ is 235 K; this value close to that cubic-SrMnO${}_{3}$ (${T}_{\mathrm{N}}$ 240 K) 4$H$-SrMnO${}_{3}$ 280 K). have the same building blocks face-sharing MnO${}_{6}$ octahedra. susceptibility exhibits behavior typical for classical three-dimensional antiferromagnets with maximum near ${T}_{\mathrm{N}}$---in contrast those 4$H$-SrMnO${}_{3}$, where broad maxima are observed far above ${T}_{\mathrm{N}}$. Isothermal magnetization curves (at 2 show an upturn deviation from linear 10 kOe, indicating possible spin--flop magnetic phase transition.