Crystal Structures and Magnetic Properties of Polyethylene Glycol (PEG-4000) Encapsulated Co0.5Ni0.5Fe2O4 Magnetic Nanoparticles

Edi Suharyadi (Department of Physics, Universitas Gadjah Mada Sekip Utara BLS 21 Yogyakarta 55281 Indonesia)
Lintang Griyanika (Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia)
Joko Utomo (Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia)
Ayu Kurnia Agustina (Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia)
Takeshi Kato (Department of Electronics, Nagoya University, Japan)
Satoshi Iwata (Institute of Materials and Systems for Sustainability, Nagoya University, Japan)

INDONESIAN JOURNAL OF APPLIED PHYSICS
Vol 8, No 2 (2018): October

Nanocrystalline mixed spinel ferrite of Co0.5Ni0.5Fe2O4 magnetic nanoparticles (MNPs) has been successfully synthesized by coprecipitation method and encapsulated by PEG-4000 with various concentrations. X-Ray Diffraction (XRD) patterns showed that nanoparticles contained Co0.5Ni0.5Fe2O4 spinel ferrite with crystallite size of 14.9 nm. After PEG-4000 encapsulation particles size decreased became 7.7 nm. Interaction Co0.5Ni0.5Fe2O4 nanoparticles with long chain PEG-4000 caused the crystal growth trap. Lattice parameter and X-Ray density have no significant difference after encapsulated PEG-4000. The coercivity (????????) of Co0.5Ni0.5Fe2O4 was 214 Oe. The ???????? decreased after PEG-4000 encapsulation became 127 Oe, which is due to the decrease of crystallite size. The maximum magnetization (Mmax) of Co0.5Ni0.5Fe2O4 was 12.0 emu/g, and decreased after PEG-4000 encapsulation to 11.7 emu/g, because PEG-4000 is paramagnetic. After the concentration of PEG-4000 increased, then the amount of paramagnetic material increase which lead maximum magnetization decrease.