Multiple magnetic transitions and electrical transport transformation of a BaFeO3 cubic perovskite single crystal

Cubic perovskite $\mathrm{BaFe}{\mathrm{O}}₃$ single crystals with stoichiometric oxygen content were successfully grown by a two-step method. With decreasing temperature, the crystal experiences a spin-glassy transition at ${T}_{\mathrm{SG}}\ensuremath{\approx}181\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, followed by a long-range spiral antiferromagnetic ordering at ${T}_N\ensuremath{\approx}117\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, and then a third spin transition at ${T}_N^{\ensuremath{'}}\ensuremath{\approx}97\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, revealing the subtle magnetic competition and interactions. As a result, a smaller magnetic field (\ensuremath{\sim}0.4 T) can induce a metamagnetic transition towards a ferromagnetic state with the saturated magnetic moment about $3.2\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}/\mathrm{f}.\mathrm{u}.$ at 2 K. The easy magnetization axis looks to vary from the direction perpendicular to [111] to the [100] axis. Semiconducting behavior with a small activation energy is observed above ${T}_{\mathrm{N}}$, whereas the spiral spin ordering changes the electrical transport to be likely half-metallic with considerable negative magnetoresistance effect.