Center for Nanomaterial & Energy Devices, School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded, 431606, India.
Dnyanopasak Shikshan Mandal's Arts, Commerce and Science College, Jintur, 431509, India.
Sci Rep. 2017 May 31;7(1):2524. doi: 10.1038/s41598-017-02784-z.
The bismuth (Bi)-doped cobalt ferrite nanostructures with dual phase, i.e. cubic spinel with space group Fd3m and perovskite with space group R3c, have been successfully engineered via self-ignited sol-gel combustion route. To obtain information about the phase analysis and structural parameters, like lattice constant, Rietveld refinement process is applied. The replacement of divalent Co by trivalent Bi cations have been confirmed from energy dispersive analysis of the ferrite samples. The micro-structural evolution of cobalt ferrite powders at room temperature under various Bi doping levels have been identified from the digital photoimages recorded using scanning electron microscopy. The hyperfine interactions, like isomer shift, quadrupole splitting and magnetic hyperfine fields, and cation distribution are confirmed from the Mossbauer spectra. Saturation magnetization is increased with Bi-addition up to x = 0.15 and then is decreased when x = 0.2. The coercivity is increased from 1457 to 2277 G with increasing Bi-doping level. The saturation magnetization, coercivity and remanent ratio for x = 0.15 sample is found to be the highest, indicating the potential of Bi-doping in enhancing the magnetic properties of cobalt ferrite.
通过自引发溶胶-凝胶燃烧法成功制备了具有双相结构的铋掺杂钴铁氧体纳米结构，即立方尖晶石相（空间群 Fd3m）和钙钛矿相（空间群 R3c）。为了获得有关相分析和结构参数的信息，如晶格常数，应用了 Rietveld 精修过程。从铁氧体样品的能量色散分析证实了二价 Co 被三价 Bi 阳离子取代。通过扫描电子显微镜记录的数字照片图像，确定了室温下不同 Bi 掺杂水平下钴铁氧体粉末的微结构演变。从穆斯堡尔光谱证实了超精细相互作用，如同质异能移、四极分裂和磁超精细场以及阳离子分布。随着 Bi 添加量的增加，饱和磁化强度增加到 x = 0.15，然后当 x = 0.2 时减少。随着 Bi 掺杂水平的增加，矫顽力从 1457 增加到 2277 G。对于 x = 0.15 样品，饱和磁化强度、矫顽力和剩余比最高，表明 Bi 掺杂在提高钴铁氧体的磁性方面具有潜力。
