High Curie temperature and coercivity performance of Fe3−xCrxSe4 nanostructures

Abstract

Monoclinic Fe_3−xCr_xSe₄ nanostructures (0 ≤ x ≤ 2.5) were synthesized using a high-temperature solution chemical method. With increasing the Cr doping, the peak positions in the X-ray diffraction (XRD) patterns of Fe_3−xCr_xSe₄ nanostructures slightly shifted to lower 2θ values due to the changes in lattice parameters. Expansions in the unit cell volumes of Fe_3−xCr_xSe₄ nanostructures (x > 0.3) may have been responsible for enhancing the ferromagnetic (FM) interaction between magnetic ions, which resulted in a significant increase in the Curie temperature (T_C) from 331 K for Fe₃Se₄ to 429 K for FeCr₂Se₄, distinctly differing from the magnetic properties of the corresponding bulk materials. A room-temperature coercivity (H_C) analysis showed an obvious increase from 3.2 kOe for Fe₃Se₄ to 12 kOe for Fe_2.3Cr_0.7Se₄ nanostructure, but gradually decreased upon further increasing the Cr content.