Preparation and characterization of Gd3+ substituted nano-structured cobalt ferrites for humidity sensor

Anu Rana, O. P. Thakur, Vinod Kumar, R. P. Pant, Bhikham Singh

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Magnetic nano-materials CoGdxFe2-xO4, (x = 0.0, 0.1, 0.3 and 0.5) were synthesized by chemical co-precipitation method. Spinel ferrite crystalline phase formation of the developed materials was confirmed by the peak positions in X-ray diffraction pattern. The developed particles were annealed at 573 K to improve their crystalline properties. The crystallite size was calculated by Debye Scherrer's formula. The average crystallite size was found to be 7 nm in the Gd3+ substituted sample (with x = 0.5) compared to 27 nm in the case of the un-substituted cobalt ferrite sample. The developed nano-particle pallets have been studied for conductivity based humidity sensors at room temperature in the humidity range of 10% RH to 80% RH. The results of our investigations reveal a strong dependence of the material electrical conductivity on the humidity and the Gd3+ concentration. The humidity sensitivity coefficient has been calculated in terms of relative change in resistance of material with humidity and it was found that among all developed nano-structured ferrite materials CoGd0.5Fe1.5O4 ferrite exhibits the highest sensitivity towards humidity with an exponential increase in electrical conductivity of more than thousand times as the humidity increases from 10% RH to 80% RH.

Original languageEnglish
Pages (from-to)1378-1382
Number of pages5
JournalSensor Letters
Issue number9
Publication statusPublished - 1 Sept 2014
Externally publishedYes


  • Co-Gd ferrites
  • Humidity
  • Nano-particles
  • Sensors
  • X-ray diffraction

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Preparation and characterization of Gd3+ substituted nano-structured cobalt ferrites for humidity sensor'. Together they form a unique fingerprint.

Cite this