Magnetic and humidity sensing properties of nanostructured Cu[x]Co[1-x]Fe2O4 synthesized by auto combustion technique

Abstract

Magnetic nanomaterials (23-43 nm) of Cu${}_x$Co${}_{1-x}$Fe${}_2$O${}_4$\ (x = 0.0, 0.5 and 1.0) were synthesized by auto combustion method. The crystallite sizes of these materials were calculated from X-ray diffraction peaks. The band observed in Fourier transform infrared spectrum near 575 cm${}^{-1}$ in these samples confirm the presence of ferrite phase. Conductivity measurement shows the thermal hysteresis and demonstrates the knee points at 475${}^o$C, 525${}^o$C and 500${}^o$C for copper ferrite, cobalt ferrite and copper-cobalt mixed ferrite respectively. The hystersis M-H loops for these materials were traced using the Vibrating Sample Magnetometer (VSM) and indicate a significant increase in the saturation magnetization (M${}_s$) and remanence (M${}_r$) due to the substitution of Cu${}^{2+}$ ions in cobalt ferrite, while the intrinsic coercivity (H${}_c$) was decreasing. Among these ferrites, copper ferrite exhibits highest sensitivity for humidity.

12 pages, 7 figures