Rapid microwave-assisted synthesis and magnetic properties of high-entropy spinel (Cr_0.2Mn_0.2Fe_0.2Co_0.2-xNi_0.2Zn_x)₃O₄ nanoparticles

High-entropy oxide (HEO) has recently become popular because of its unique multifunctional performance. In this study, we developed a novel microwave-assisted method for the production of HEO nanoparticles with the composition (Cr_0.2Fe_0.2Mn_0.2Co_0.2-xNi_0.2Zn_x)₃O₄ (x = 0, 0.05, 0.1, and 0.2). The results revealed that all metallic elements were uniformly distributed throughout the single-phase cubic spinel structure of the HEO nanoparticles. The particle size distributions of four fabricated samples ranged from 10 to 50 nm. Because of its numerous advantages such as the ultrafast and low-temperature fabrication of nanoscale and high-purity products at a relatively low cost, the suggested methodology is an excellent synthesis method. The original HEO spinel (x = 0) achieved saturated magnetization (M_s) and coercivity (H_c) values of 24.3 emu/g and 160 Oe, respectively, at room temperature. Zinc substitution in the HEO composition indicated that M_s and H_c decreased with increasing zinc concentration owing to its non-magnetic nature.