Ahad Abdul, Hossain A K M Akther
Department of Physics, Bangladesh University of Engineering & Technology, Dhaka, 1000, Bangladesh.
Heliyon. 2024 Feb 15;10(4):e26050. doi: 10.1016/j.heliyon.2024.e26050. eCollection 2024 Feb 29.
Mn-substituted Cu and Zn co-doped spinel-typed nano-crystalline ferrites having nominal composition NiMnCuZnFeO (x = 0.00-0.25 in 0.05 increments) have been prepared through the citric acid assisted sol-gel auto-combustion technique. From the XRD measurements, it was found that several intense peaks ensured the cubic spinel-based ferrite structure beyond the formation of any impurity peaks. The crystallite sizes varied from 20 to 28 nm for ash-burnt powders following the coalescence process that decreased the lattice defects and strain. With an increase in Mn concentration, the hopping length (L) of the tetrahedral A-site increases, while the hopping length (L) of the octahedral B-site decreases with enhanced lattice constant. The sintered samples' average grain sizes, as measured using the Field Emission Scanning Micrographs (FESEM), differed from around 1.40 to 5.30 μm. Incorporating Mn-ion accelerates grain growth and crystallite size with increased bulk density and reduced porosity due to heat treatment. For increasing sintering temperature along with Mn concentration, porosity drops from 42% to 3%, resulting in enhancing the magnetic induction of the prepared ferrites. The 25% Mn substituted composition displays the maximum initial permeability ( = 315), which is ∼7 times larger than the pristine composition. Due to the reduction of Ni content, the relative quality factor rises but the magnetic loss tangent reduces. An increased trends of are accompanied by decreased resonant frequency, obeying Snoek's law. According to the experimental findings, the high spin Mn substitution in the composition causes the saturation magnetization to increase while the coercivity and Néel temperature drop with increasing grain size. Hence, the locally prepared low-cost Nano-crystalline Ni-Mn-Cu-Zn ferrites bearing excellent properties can be a good candidate for promising future applications in nanotechnology.
通过柠檬酸辅助溶胶 - 凝胶自燃烧技术制备了标称组成为NiMnCuZnFeO（x = 0.00 - 0.25，增量为0.05）的锰取代的铜和锌共掺杂尖晶石型纳米晶铁氧体。通过X射线衍射测量发现，几个强峰确保了基于立方尖晶石的铁氧体结构，未形成任何杂质峰。对于经过聚结过程的灰烧粉末，微晶尺寸在20至28纳米之间变化，该过程减少了晶格缺陷和应变。随着锰浓度的增加，四面体A位的跳跃长度（L）增加，而八面体B位的跳跃长度（L）随着晶格常数的增加而减小。使用场发射扫描显微镜（FESEM）测量的烧结样品的平均晶粒尺寸在约1.40至5.30μm之间变化。由于热处理，掺入锰离子会加速晶粒生长和微晶尺寸，同时增加堆积密度并降低孔隙率。随着烧结温度和锰浓度的增加，孔隙率从42％降至3％，从而提高了制备的铁氧体的磁感应强度。25％锰取代的组合物显示出最大初始磁导率（μ = 315），比原始组合物大7倍左右。由于镍含量的降低，相对品质因数上升，但磁损耗正切降低。根据斯诺克定律，随着共振频率的降低，磁导率呈增加趋势。根据实验结果，组合物中高自旋锰的取代导致饱和磁化强度增加，而矫顽力和奈耳温度随着晶粒尺寸的增加而下降。因此，本地制备的具有优异性能的低成本纳米晶镍 - 锰 - 铜 - 锌铁氧体可能是未来纳米技术中很有前景的应用的良好候选材料。
