Structure and magnetic properties of a class of spinel high-entropy oxides

• Published in: Journal of magnetism and magnetic materials 2021-10, Vol.535, p.168063, Article 168063
• Main Authors: Zhu, Haiyang, Xie, Huidong, Zhao, Yihan, Dai, Saifei, Li, Mingya, Wang, Xiaoqiang
• Format: Article
• Language: English
• Subjects: Aluminum; Chromium; Cobalt; Combustion synthesis; Crystal structure; Crystallites; Entropy; High-entropy oxides; Hysteresis loops; Iron; Lattice parameters; Magnetic moments; Magnetic properties; Magnetic property; Magnetism; Manganese; Nickel; Phase composition; Spinel
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2021.168063

•A class of high-entropy oxides were prepared by solution combustion synthesis method.•All the samples show the ferromagnetic property.•The magnetic property can be controlled by element substitution.•All the grains in high-entropy oxides are single domain. A class of high-entropy spinel oxides system, (Al,Cr,Fe,Mn,Ni)3O4, (Co,Cr,Al,Mn,Ni)3O4, (Co,Cr,Fe,Al,Ni)3O4, (Co,Cr,Fe,Mn,Al)3O4, (Co,Cr,Fe,Mn,Ni,Al)3O4 nanocrystalline powders, have been prepared by the solution combustion synthesis method with the temperature at 550 °C, 650 °C, and 750 °C. The phase composition analysis of the samples shows that all samples are single-phase spinel structure (Fd-3 m) and the crystalline size and lattice constant increase as temperature goes up. Furthermore, magnetic hysteresis loops indicate that magnetic moment and crystallite size can be controlled through non-magnetic Al3+, making it possible to achieve tailorable magnetic property. XPS results show that in all HEOs, the valence of Fe is + 3, the valence of Co is + 8/3 (+2: +3 = 1:1), the valence of Ni is + 2, the valence of Cr is + 3, the valence of Mn is + 3. The magnetic difference between the HEOs is caused by element substitution.