Magnetic and structural characterization of Nb 3+ -substituted CoFe 2 O 4 nanoparticles
Yükleniyor...
Tarih
2019
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Ltd
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
This study investigated the effect of Nb 3+ substitution on the magnetic and structural properties of CoFe 2 O 4 nanoparticles (NPs) synthesized by hydrothermal approach. The formation of a single phase of spinel ferrite was confirmed through X-ray powder diffraction, and crystallite sizes in the range 18–30 nm were observed. Moreover, it found that the Fourier transform infrared (FT-IR) spectra of the NPs included the main vibration bands of the spinel structure. The partially cubic structure was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The energy band gaps for CoNb x Fe 2-x O 4 were estimated to be in the range 0.48–0.53 eV for Nb 3+ content x = 0.0–0.10. Magnetization measurements at room temperature (RT; 300 K) and at 10 K were performed on spinel CoNb x Fe 2-x O 4 (0.00 ? x ? 0.10) NPs using a vibrating sample magnetometer (VSM). Nb 3+ doping significantly changed the magnetization and coercivity of the Co ferrite samples. RT hysteresis curves indicated well-defined ferrimagnetic behavior for all prepared NPs with saturation magnetization (M s ) in the range 44.45 – 49.40 emu/g and remanent magnetization (M r ) in the range 12.16 – 17.90 emu/g. The coercive field (H c ) is found to be equal 936 Oe and is decreased with Nb 3+ substitutions. However, hysteresis curves at 10 K showed finite remanent specific magnetization (1.90–6.70 emu/g) but significant asymmetric coercivity (715–2810 Oe), particularly for the Nb 3+ -doped samples. At 10 K, the magnetization values were 4–6 times smaller but symmetric coercivity field values were 2–3 times larger compared with the RT-VSM curves. The obtained magnetic parameters indicated the semi-hard magnetic character of the Co ferrite samples at low temperatures. © 2019 Elsevier Ltd and Techna Group S.r.l.
Açıklama
Anahtar Kelimeler
CoFe 2 O 4, Magneto-optical properties, Substituted spinel ferrites, TEM analysis
Kaynak
Ceramics International
WoS Q Değeri
Scopus Q Değeri
Q1
Cilt
45
Sayı
7
