Investigation of structural, magnetic and magnetocaloric properties of ho and fe substituted cocr2o4 spinel nanoparticles

In this study, structural, magnetic and magnetocaloric properties of Co(Cr1-xFex)2O4 (0.0≤x≤1.0) spinel multiferroic compounds produced by sol-gel method were investigated. Structural, morphological and elemental properties of all synthesized compounds were investigated by measuring X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy-Dispersive X-Ray Spectrometry (EDS). It is determined that Co(Cr1-xFex)2O4 (0.0≤x≤1.0) spinel materials have cubic crystal structure and the lattice parameter increases with increasing Fe content. In addition, it is observed from the SEM images that the particle size increases with Fe content. From the elemental analysis results, it has been determined that the atomic percent ratios of the synthesized compounds are close to the desired values. It is observed that the magnetization values both temperature and magnetic field dependence increase with increasing of Fe content in the main structure. It is determined that the magnetic transition temperature increases with increasing Fe content in the main structure. Magnetic entropy change of the samples is determined from isothermal magnetization measurements taken in the magnetic transition temperature region. Furthermore, various concentrations of Ho3+ ions were substituted by Cr3+ and Fe3+ ions in CoCrFeO4. The structural, magnetic and magnetocaloric properties of the synthesized Ho-substituted CoCrFeO4 compounds were investigated using the measurement methods mentioned above. No significant change in magnetic transition temperature is observed by Ho3+ ions in CoCrFeO4 compound. However, it is observed that the magnetization value decreases with increasing amount of Ho.