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要旨:
Cubic perovskite BaFeO3 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-SG approximate to 181 K, followed by a long-range spiral antiferromagnetic ordering at T-N approximate to 117 K, and then a third spin transition at T'(N) approximate to 97K, revealing the subtle magnetic competition and interactions. As a result, a smaller magnetic field (similar to 0.4 T) can induce a metamagnetic transition towards a ferromagnetic state with the saturated magnetic moment about 3.2 mu(B)/f.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 TN, whereas the spiral spin ordering changes the electrical transport to be likely half-metallic with considerable negative magnetoresistance effect.
