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The effect chromium doping in cobalt ferrites, in the nano scale, has been studied. Structure, morphology, electrical and magnetic transport of CoFe2-xCrxO4 (x = 0, 0.5, 1, 1.5) has been investigated in detail. Sol-gel method has been used to get nano crystalline size of the prepared spinel structure. The formed gel has been fired at 600 °C temperature. Single cubic crystal phase is formed according to analysis of X-ray diffraction patterns and infra-red spectra. The decrease in both the lattice constant and the crystalline size has been observed as a result of Cr doping. Moreover, the electron density inside the unit cell has decreased as a result of Cr doping. All samples have been homogenously formed in the nano-crystallized size in the range from 7 to 16 nm. There has been a phase transformation (exothermic peak) at point 342 °C for x = 0.0 and 362 °C for samples containing extra Cr ions for the DSC curve. The two essential absorption bands ν1 and ν2 have been observed in the range 560–610 (for all prepared samples) and 420 cm−1 (for all doped samples with Cr ions), respectively for infra red analysis. The electrical properties have showed semiconductor behavior. The magnetic properties of these compounds have been studied. They have demonstrated ferrimagnetic ordering type. From the magnetic hysteresis loop, it has been noted that the coercivity HCi has decreased as a result of the substitution of iron with chrome. CoFe2O4 has been higher coercivity of 1595.4G and the coercivity has decreased to be 114.6G for CoFe0.5Cr1.5O4. |
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