Synthesis and magnetic properties of NiCo2O4urchin-like nanofibers

Ahmed M Nashaat; Abdulaziz Abu El-Fadl; Hiroyuki Nakamura; Mohamed A Kassem

doi:10.1088/1361-6528/ad947f

Synthesis and magnetic properties of NiCo₂O₄urchin-like nanofibers

Nanotechnology. 2024 Dec 11;36(8). doi: 10.1088/1361-6528/ad947f.

Authors

Ahmed M Nashaat^{1

2

3}, Abdulaziz Abu El-Fadl^{1

2}, Hiroyuki Nakamura³, Mohamed A Kassem^{1

2

3}

Affiliations

¹ Department of Physics, Faculty of Science, Assiut University, 71516 Assiut, Egypt.
² Laboratory of Smart Materials for Energy Futures, Department of Physics, Faculty of Science, Assiut University, 71516 Assiut, Egypt.
³ Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan.

PMID: 39569849
DOI: 10.1088/1361-6528/ad947f

Abstract

Single-phase NiCo₂O₄(NCO) nanoparticles (NPs) with an average particle size of 12 (±3.5) nm were successfully synthesized as aggregates in urchin-like nanofibers via a hydrothermal route. Magnetization data measured as functions of temperature and magnetic field suggest a superparamagnetic-like behavior at room temperature, a ferrimagnetic transition around a Curie temperatureT_C∼ 200 K, and a spin blocking transition at a blocking temperatureT_B∼ 90 K, as observed at a field of 100 Oe. The spin blocking nature has been investigated by analyses of the field-dependence ofT_Bin the static magnetization and its frequency-dependence in the ac susceptibility data measured in zero-field cooling regime, both indicate a low-temperature spin glass-like state. BelowT_B, the coercivity increases monotonically up to 1.7 kOe with decreasing temperature down to 5 K. Our results indicate that the magnetic behavior of NCO NPs, which is mainly determined by the cations' ratio, oxidation states, and site-occupancy, can be controlled by a synthesis in appropriate particle size and morphology.

Keywords: NiCo2O4; cluster spin glass; magnetic double exchange; magnetic nanoparticles; spinel cobaltite; superparamagnetic state.