title: Enhanced magnetic anisotropy and heating efficiency in multi-functional manganese ferrite/graphene oxide nanostructures.
abstract: A promising nanocomposite material composed of MnFe2O4 (MFO) nanoparticles of ∼17 nm diameter deposited onto graphene oxide (GO) nanosheets was successfully synthesized using a modified co-precipitation method. X-ray diffraction, transmission electron microscopy, and selected area electron diffraction confirmed the quality of the synthesized samples. Fourier transform infrared measurements and analysis evidenced that the MFO nanoparticles were attached to the GO surface. Magnetic measurements and analysis using the modified Langevin model evidenced the superparamagnetic characteristic of both the bare MFO nanoparticles and the MFO-GO nanocomposite at room temperature, and an appreciable increase of the effective anisotropy for the MFO-GO sample. Magnetic hyperthermia experiments performed by both calorimetric and ac magnetometry methods indicated that relative to the bare MFO nanoparticles, the heating efficiency of the MFO-GO nanocomposite was similar at low ac fields (0-300 Oe) but became progressively larger with increasing ac fields (>300 Oe). This has been related to the higher effective anisotropy of the MFO-GO nanocomposite. In comparison with the bare MFO nanoparticles, a smaller reduction in the heating efficiency was observed in the MFO-GO composites when embedded in agar or when their concentration was increased, indicating that the GO helped minimize the physical rotation and aggregation of the MFO nanoparticles. These findings can be of practical importance in exploiting this type of nanocomposite for advanced hyperthermia. Magnetoimpedance-based biodetection studies also indicated that the MFO-GO nanocomposite could be used as a promising magnetic biomarker in biosensing applications.
authors.affiliation: Department of Nanoscience and Nanotechnology-DoNST, Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (HUST), 01 Dai Co Viet Street, Hai Ba Trung District, Hanoi 10000, Vietnam.
authors.forename: Anh-Tuan
authors.initials: AT
authors.lastname: Le
authors.forename: Chu Duy
authors.initials: CD
authors.lastname: Giang
authors.forename: Le Thi
authors.initials: le T
authors.lastname: Tam
authors.forename: Ta Quoc
authors.initials: TQ
authors.lastname: Tuan
authors.forename: Vu Ngoc
authors.initials: VN
authors.lastname: Phan
authors.forename: Javier
authors.initials: J
authors.lastname: Alonso
authors.forename: Jagannath
authors.initials: J
authors.lastname: Devkota
authors.forename: Eneko
authors.initials: E
authors.lastname: Garaio
authors.forename: José Ángel
authors.initials: JÁ
authors.lastname: García
authors.forename: Rosa
authors.initials: R
authors.lastname: Martín-Rodríguez
authors.forename: Ma Luisa
authors.initials: ML
authors.lastname: Fdez-Gubieda
authors.forename: Hariharan
authors.initials: H
authors.lastname: Srikanth
authors.forename: Manh-Huong
authors.initials: MH
authors.lastname: Phan