自形成MnFe_2O_4磁性液体的制备和磁性(英文)

Preparation and Magnetization for Self-Formed MnFe_2O_4 Ferrofluids

用化学共沉淀法制备MnFe2O4纳米微粒,并且采用自形成法制备了粒子型磁性液体.在这种磁性液体中,通过适当的酸蚀,Mn2+和Fe3+离子从MnFe2O4纳米微粒溶解并吸附在磁性微粒表面以阻止微粒团聚.微粒和磁性液体都呈磁滞回线.这种磁化性质可能来源于在高场下产生的不可逆团聚.

MnFe2O4 nanoparticles are prepared by chemical coprecipitation method. Based on the MnFe2O4 nanoparticles, a self-formed ionic ferrofluid is synthesized. In the ferrofluid, Mn^2- and Fe^3＋ ions dissolved from the MnFe2O4 nanoparticles via suitable acid attack are adsorbed on the surface of the magnetic particles, thus preventing the particles from aggregating. The average thickness of ionized layers of the ferrofluid particles is about 1 to 2 nm. Both the particles and the ferrofluids have hysteresis behavior. The behavior may result from irreversible aggregation induced under high magnetic field.