MAGNETIC AND STRUCTURAL STUDIES OF (Sn, Ni -Sn) SUBSTITUTED BARIUM HEXAFERRITES SYNTHESIZED BY BALL MILLING

Samples of BaFe12-2x(SnSn)xO19 and BaFe12-2x(NiSn)xO19 were processed by high energy milling with 0 ≤ x ≤ 0.4 and 0 ≤ x ≤ 0.3 respectively. Sn2+-Sn4+ mixture considerably improved the saturation magnetization, Ms, (from 60.9 to 66.15 A.m²/kg) and diminished quickly the intrinsic coercivity, Hci, (381.1-72.33 kA/m) to suitable values for high-density magnetic recording applications, with low substitution values. On the other hand, the Ni2+-Sn4+ mixture also decreased the coercivity rapidly (diminution ~ 75%) however without enhancing the saturation magnetization. The shown differences on magnetic properties were mainly due to both magnetic nature of divalent ion and secondary phase presence. Mixtures with Sn2+ as partner ion diminished markedly to Tc (~21%).