Size dependent structural and magnetic properties of Co(1−x) Nix Cr2O4 nanoparticles (x = 0.15, 0.20)

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This study examines the structural and magnetic characteristics of Co(1−x)NixCr2O4 (x = 0.15, 0.20) compounds synthesised using the co-precipitation technique and calcined at 500 °C and 900 °C respectively. X-ray diffraction studies reveal the structure of the synthesized samples is face-centered cubic with space group Fd-3m. The particle sizes and morphology were examined by using transmission electron microscopy, and the size ranges from 64 ± 10 nm to 105 ± 15 nm for the 900 °C and 7 ± 2 and 8 ± 2 nm for the 500 °C calcined samples. Field-cooling and zero-field-cooling magnetization measurement protocols were used to investigate the materials' magnetic characteristics. The Curie temperature (TC) decreases from 91 ± 0.5 K to 85 ± 0.3 K as the Ni concentration increases from x = 0.15–0.20. Additionally, an increase in the TC value is seen for both compositions when the particle size is decreased. Spiral ordering is observed at a transition temperature TS for the samples calcined at 900 °C, while no evidence for TS was seen for samples calcined at 500 °C. Magnetization measurements as a function of field, Mμ0H, at several constant temperatures, show that the coercivity reduces with an increase in temperature in all samples. The Co(1−x)NixCr2O4 (x = 0.15, 0.20) samples calcined at 900 °C exhibit superparamagnetic behaviour with a small ferrimagnetic hysteresis loop. Furthermore, this paper evaluates the contribution of ferrimagnetic, superparamagnetic, and paramagnetic phases to the total Mμ0H curve for Co(1−x)NixCr2O4 (x = 0.15, 0.20) calcined at 900 °C through simulation. In addition, a modified Langevin simulation, incorporating a particle size distribution term, is performed for the Co(1−x)NixCr2O4 (x = 0.15, 0.20) samples calcined at 500 °C. From the simulations, it is clear that all samples show evidence of significant superparamagnetic contributions to the total saturation magnetization because of the small particles present.

Original languageEnglish
Article number107376
JournalMaterials Today Communications
Publication statusPublished - Dec 2023


  • Chromites
  • Ferrimagnetism
  • Langevin
  • Magnetic properties
  • Size dependent
  • Superparamagnetism

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Materials Chemistry


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