Satish Mudalagiriyappa, Shashanka Hadonahalli Munegowda, Saha Sujoy, Haritha Keerthi, Das Debabrata, Anantharamaiah Pendaranahalli Nadikeraiah, Ramana C V
Department of Chemistry, Faculty of Mathematical and Physical Sciences, M. S. Ramaiah University of Applied Sciences, Bangalore 560058, India.
Materials Research Centre, Indian Institute of Science, Bangalore 560012, India.
ACS Appl Mater Interfaces. 2023 Mar 29;15(12):15691-15706. doi: 10.1021/acsami.2c23025. Epub 2023 Mar 20.
This work reports on the effect of substituting a low-anisotropic and low-magnetic cation (Ni, 2μ) by a high-anisotropic and high-magnetic cation (Co, 3μ) on the crystal structure, phase, microstructure, magnetic properties, and magnetostrictive properties of NiFeO (NFO). Co-substituted NFO (NiCoFeO, NCFO, 0 ≤ ≤ 1) nanomaterials were synthesized using glycine-nitrate autocombustion followed by postsynthesis annealing at 1200 °C. The X-ray diffraction measurements coupled with Rietveld refinement analyses indicate the significant effect of Co-substitution for Ni, where the lattice constant () exhibits a functional dependence on composition (). The -value increases from 8.3268 to 8.3751 Å (±0.0002 Å) with increasing the "" value from 0 to 1 in NCFO. The - functional dependence is derived from the ionic-size difference between Co and Ni, which also induces grain agglomeration, as evidenced in electron microscopy imaging. The chemical bonding of NCFO, as probed by Raman spectroscopy, reveals that Co()-substitution induced a red shift of the T(2) and A(1) modes, and it is attributed to the changes in the metal-oxygen bond length in the octahedral and tetrahedral sites in NCFO. X-ray photoelectron spectroscopy confirms the presence of Co, Ni, and Fe chemical states in addition to the cation distribution upon Co-substitution in NFO. Chemical homogeneity and uniform distribution of Co, Ni, Fe, and O are confirmed by EDS. The magnetic parameters, saturation magnetization (), remnant magnetization (), coercivity (), and anisotropy constant () increased with increasing Co-content "" in NCFO. The magnetostriction (λ) also follows a similar behavior and almost linearly varies from -33 ppm ( = 0) to -227 ppm ( = 1), which is primarily due to the high magnetocrystalline anisotropy contribution from Co ions at the octahedral sites. The magnetic and magnetostriction measurements and analyses indicate the potential of NCFO for torque sensor applications. Efforts to optimize materials for sensor applications indicate that, among all of the NCFO materials, Co-substitution with = 0.5 demonstrates high strain sensitivity (-2.3 × 10 m/A), which is nearly 2.5 times higher than that obtained for their intrinsic counterparts, namely, NiFeO ( = 0) and CoFeO ( = 1).
本工作报道了用高各向异性和高磁性阳离子（Co，3μ）取代低各向异性和低磁性阳离子（Ni，2μ）对NiFeO（NFO）的晶体结构、相、微观结构、磁性和磁致伸缩性能的影响。采用甘氨酸 - 硝酸盐自燃烧法合成了Co取代的NFO（NiCoFeO，NCFO，0≤≤1）纳米材料，随后在1200℃进行合成后退火。结合Rietveld精修分析的X射线衍射测量表明Co取代Ni具有显著影响，其中晶格常数（）对成分（）呈现函数依赖性。在NCFO中，随着“”值从0增加到1，值从8.3268 Å增加到8.3751 Å（±0.0002 Å）。 - 函数依赖性源于Co和Ni之间的离子尺寸差异，这也导致了晶粒团聚，电子显微镜成像证明了这一点。通过拉曼光谱探测的NCFO化学键表明，Co（）取代导致T（2）和A（1）模式发生红移，这归因于NCFO八面体和四面体位置中金属 - 氧键长度的变化。X射线光电子能谱证实了除了NFO中Co取代后的阳离子分布外，还存在Co、Ni和Fe的化学状态。EDS证实了Co、Ni、Fe和O的化学均匀性和均匀分布。在NCFO中，随着Co含量“”的增加，磁参数饱和磁化强度（）、剩余磁化强度（）、矫顽力（）和各向异性常数（）增加。磁致伸缩（λ）也呈现类似行为，几乎线性地从 - 33 ppm（ = 0）变化到 - 227 ppm（ = 1），这主要是由于八面体位置的Co离子具有高磁晶各向异性贡献。磁性和磁致伸缩测量与分析表明NCFO在扭矩传感器应用方面具有潜力。针对传感器应用优化材料的努力表明，在所有NCFO材料中， = 0.5的Co取代表现出高应变灵敏度（ - 2.3×10 m/A），这几乎是其本征对应物NiFeO（ = 0）和CoFeO（ = 1）的2.5倍。
