Abstract
This research is the basic study of temperature-sensitive ferrite characteristics prepared by coprecipitation with doping different typical sizes of rare earth elements. Ni 0.5 Zn 0.5 Re x Fe 2-x O 4 (NZRF) (X = 0.02, 0.05, 0.07 and 0.09) nanoparticles (NPs) doped by Sc, Dy and Gd prepared by chemical coprecipitation method. The structure and properties of Ni 0.5 Zn 0.5 Re x Fe 2-x O 4 were analyzed by various characterization methods. XRD results show that the grain size of Ni 0.5 Zn 0.5 Re x Fe 2-x O 4 is from 10.6 to 12.4 nm, which is close to the average grain size of 13.9 nm observed on TEM images. It is also found that the ferrite particles are spherical and slightly agglomerated in TEM images. FTIR measurements between 400 and 4000 cm -1 have confirmed the intrinsic cation vibration of the spinel structure. The concentrations of nickel, zinc, iron, and rare earth elements have been determined by ICP-AES, and all ions have participated in the reaction. The magnetic properties of Sc, Dy, and Gd 3+ doped NZRF NPs at room temperature are recorded by a physical property measurement system (PPMS-9). It is found that the magnetization can be changed by adding rare-earth ions. When X = 0.07, Gd 3+ doped Ni 0.5 Zn 0.5 Fe 2 O 4 (NZF) exhibits the highest saturation magnetization. The magnetic properties of NZGd 0.07 vary the most with temperature. The thermomagnetic coefficient of NZGd 0.07 nanoparticles stabilized to 0.18 emu/gK at 0-100℃. Hence, NZGd 0.07 with low Curie temperature and the high thermomagnetic coefficient can be used to prepare temperature-sensitive ferrofluid. All the samples exhibit very small coercivity and almost zero remanences, which indicates the superparamagnetism of the synthesized nanoparticles.
Structure and magnetic properties of coprecipitated nickel-zinc ferrite-doped rare earth elements of Sc, Dy, and Gd
