Understanding microstructural evolution and soft magnetic properties in nanocrystallized metallic glass Fe68.5Cu1Nb3Si18.5B9

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology Vol. 15; no. 1
• Main Authors: Srivastava, A. P., Srivastava, D., Sharma, S. K., Pujari, P. K., Suresh, K. G., Dey, G. K.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2013; Springer
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Inorganic Chemistry; Lasers; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Magnetic properties and materials; Magnetic properties of nanostructures; Materials Science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanotechnology; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Research Paper; Small particles and nanoscale materials; Studies of specific magnetic materials; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Nanoparticles; Soft magnetic material; Metallic glass; Positron annihilation spectroscopy; Particle size; Annealing; Vacancies; Metastable phases; Crystallization; Positron annihilation; XRD; Nanostructures; Interfaces; Metallic glasses; Transmission electron microscopy; Coercive force; Phase equilibria; Magnetic materials; Microstructure; Nanostructured materials; Nanocrystal; Saturation magnetization; Magnetic properties
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-012-1357-8

Microstructural evolution during nanocrystallization of amorphous metallic glass Fe
68.5
Si
18.5
Nb
3
B
9
Cu
1
has been studied. The effect of microstructural features of nanocrystalline phases on soft magnetic properties have been evaluated and rationalized with existing theoretical models. The TEM and XRD studies have shown the presence of single Fe
3
Si nanocrystalline phase at 550 °C (size range 13–16 nm) and three nanocrystalline phases Fe
3
Si, Fe
3
B, and Fe
2
B at 800 °C (size range 18–100 nm). Increase in annealing time at 800 °C resulted in decomposition of metastable Fe
3
B phase to equilibrium Fe
2
B phase. Positron annihilation spectroscopy revealed the presence of nanovoids in amorphous samples. Theoretical estimations showed that these nanovoids were having free volume equivalent to that of a vacancy defect consisting of five or more atoms vacancy cluster present in the amorphous samples. Nature of interfaces associated with nanocrystalline phases could be characterized using positron annihilation spectroscopy. This study showed that metallic nanoparticles have very low concentration of thermal vacancies. Effects of nature of phases, particle density, and nanoparticle size on saturation magnetization and coercivity have been studied.