Magnetic properties of bafe_12-(x+y)sn_xco_yo₁₉ single crystals

Magnetic properties of BaFe_12-(x+y)Sn_xCo_yO₁₉ single crystals, with 0 ≤ x ≤ 2 and 0 ≤ y ≤ 2, have been investigated in the temperature range 6 to 320 K with a varying field from -5 to + 5 T applied parallel and perpendicular to the c-axis. It is found that when Fe³⁺ is substituted by Co²⁺ and Sn²⁺, the anisotropy and saturation magnetization of these materials are reduced. With x+y < 1.5, the sample exhibits long range magnetic ordering with the uniaxial anisotropy in the c-axis. When the substitution was increased to x+y = 2.5, the long distance magnetic coupling is partially destroyed, and the sample behaves as a weakly long-range anisotropy granular material. At x+y ∼ 4, the sample shows reentrant spin glass behavior.