Vats Nishtha, Phadkule Saket Sanjay, Sarma Shrutidhara, Negi Devendra Singh, Vishal Badri, Vadera Sampat Raj, Mishra Durgamadhab
Department of Physics, Indian Institute of Technology, N H 62, Nagaur Road, Karwar, Jodhpur, 342037, Rajasthan, India.
Department of Mechanical Engineering, Indian Institute of Technology, N H 62, Nagaur Road Karwar, Jodhpur, 342037, Rajasthan, India.
Sci Rep. 2025 Jul 2;15(1):23314. doi: 10.1038/s41598-025-04493-4.
This work reports a simple yet unique way of tailoring the morphology of M-type Strontium Hexaferrite, SrFeO (SFO) particles inside the nanofibers. The reported materials were synthesized by the polymer-sol-assisted electrospinning technique followed by calcination. Calcination temperature and rate of heating play significant role in controlling the morphology of SFO nanofibers in terms of shapes, size and distribution thereby having a direct bearing on the resultant magnetic properties. The synthesized materials were investigated using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), Thermogravimetric-Differential Thermal Analysis (TG-DTA), and Magnetic Property Measurement System (MPMS). The XRD analysis shows formation of almost phase pure SFO with very minute quantities of secondary phase as hematite. The FESEM images show wide range of morphologies of SFO nanofibers and specifically the nanoparticles present within the nanofibers (from irregular to platelet-like shape) thereby demonstrating the tailoring of morphologies of not only of nanofibers but nanoparticles within the nanofibers simply through variations of two parameters viz. calcination temperature and rate of heating. The TG-DTA results show that complete decomposition of PVP and formation of the SFO crystallization takes place at a much lower temperature of 422 C. The room temperature hysteresis measurement showed that the sample calcined at 800 C at heating rate of 10 C/min has shown enhanced magnetic properties (M, M, and H) than the samples calcined at 600 C and 950 C. The HRTEM studies show that the variation in heating rate also yields interesting variations in morphology of nanoparticles and their arrangement within nanofibers. This research work has resulted in a unique pathway of synthesizing nanofibers with controlled and variable morphology.
这项工作报道了一种简单而独特的方法来调整纳米纤维内部M型六铁酸锶（SrFeO，SFO）颗粒的形态。所报道的材料通过聚合物溶胶辅助静电纺丝技术合成，随后进行煅烧。煅烧温度和加热速率在控制SFO纳米纤维的形状、尺寸和分布等形态方面起着重要作用，从而直接影响最终的磁性能。使用X射线衍射（XRD）、场发射扫描电子显微镜（FESEM）、高分辨率透射电子显微镜（HRTEM）、热重-差热分析（TG-DTA）和磁性测量系统（MPMS）对合成材料进行了研究。XRD分析表明形成了几乎纯相的SFO，仅有极少量的次生相赤铁矿。FESEM图像显示了SFO纳米纤维的多种形态，特别是纳米纤维内存在的纳米颗粒（从不规则形状到片状），从而证明了仅通过煅烧温度和加热速率这两个参数的变化，不仅可以调整纳米纤维的形态，还可以调整纳米纤维内纳米颗粒的形态。TG-DTA结果表明，聚乙烯吡咯烷酮（PVP）在422℃的较低温度下完全分解并形成SFO晶体。室温磁滞测量表明，在10℃/min加热速率下于800℃煅烧的样品比在600℃和950℃煅烧的样品具有更强的磁性能（M、M和H）。HRTEM研究表明，加热速率的变化也会使纳米颗粒的形态及其在纳米纤维内的排列产生有趣的变化。这项研究工作为合成具有可控和可变形态的纳米纤维开辟了一条独特的途径。
