Structural and room temperature ferromagnetic properties of Fe3+-Doped CuCrO2 fibers

Abstract

Undoped CuCrO2 and Fe-doped CuCrO2 fibers at 3, 5 and 10 at.% were synthesized using an electrospinning method and calcined at 865 °C for 7 h under a vacuum. X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) methodology and vibrating sample magnetometry (VSM) were used to analyze the synthesized samples. Characterization from XRD patterns indicated a single phase delaffosite-type CuCrO2 in all samples. Lattice parameters, a and c, increased to 2.987 Å and 17.122 Å, respectively, at a 10 at.% level of Fe3+ dopant compared to that of undoped CuCrO2 where a was 2.974 Å and c was 17.094 Å. SEM and TEM results confirmed the morphology of CuCrO2 fibers with an average diameter in the range of 0.67 ± 0.20 to 1.85 ± 0.57 μm. Specific surface areas of all synthesized fibers were investigated using BET methodology. With magnetic characterization obtained from VSM results, undoped CuCrO2 showed ferromagnetic (FM) behavior at room temperature (RT) with a magnetization (M) value of 0.0016 emu/g. All samples of Fe-doped CuCrO2 fibers displayed RT-FM behavior, with higher M values than that of undoped CuCrO2, 0.0224 emu/g at 10 at.% Fe. Indirect superexchange and double-exchange mechanisms are discussed in this work. The novelty of this work on the prepared fibers is the observation of a single phase of CuCrO2 in undoped and Fe-doped CuCrO2 fibers with a high dopant concentration of 10 at.% and showing RT-FM for all prepared Fe-doped CuCrO2 fibers.