Study on Bi—Fe3O4 nanocomposite prepared via mechanochemical processing

In this work Bi-Fe 3 O 4 nanocomposite was synthesized by room temperature milling of Bi 2 O 3 and Fe powders using a planetary ball mill in air. The synthesis reaction proceeds with increase in milling time and is finished by about 4 h. The XRD pattern of the as-milled powder shows that the main phases are Bi and Fe 3 O 4 without any extra phases. The average crystallite sizes of the constituents have been determined by Scherrer’s formula and they were 22 and 18 nm for Bi and Fe 3 O 4 respectively. This was also confirmed by Transmission Electron Microscopy (TEM). Magnetic hysteresis loops at room temperature were recorded using a vibrating sample magnetometer (VSM). A tow-probe method was used to measure resistivity variation of the nanocomposite as a function of magnetic filed and temperature. We have observed a room temperature magnetoresistance (ρ 0 — ρ H )/ρ 0 as large as 17% in a magnetic field of 1 T.