Domain structures of nanocrystalline Fe90Zr7B3 alloy studied by Lorentz microscopy
Open Access
- 1 July 2003
- journal article
- Published by Taylor & Francis Ltd in Science and Technology of Advanced Materials
- Vol. 4 (4), 353-359
- https://doi.org/10.1016/j.stam.2003.09.001
Abstract
As-quenched Fe90Zr7B3 alloy has been crystallized at 773, 923 and 973 K, it is found that the specimens annealed at 773 and 923 K have grains with the same size, but the one annealed at 773 K has a thick amorphous matrix and a broad grain size distribution. Big domains and smooth domain walls are observed in the specimen annealed at the optimum condition (923 K), and excellent magnetic softness is obtained. On the other hand, the one annealed at 973 K has very large grains (40 nm). Very small domains with irregular walls are observed, indicating a weak intergranular exchange coupling.Through in situ Lorentz microscopy, a relaxation of internal stress in the specimen annealed at 773 K is observed at an elevated temperature (333 K). The internal stress observed is considered to be one of the important factors that degrade the soft magnetic properties. Based on the results of differential thermal analysis, a two-step annealing, where the as-quenched specimen is pre-heated at 723 K and subsequently annealed at 773 K, is utilized. The domain structure of the specimen treated by the two-step annealing is analyzed. It is found that the size of the domain is larger than that of the specimen annealed at 773 K, suggesting the possibility of control of the soft magnetic properties.Keywords
This publication has 14 references indexed in Scilit:
- Magnetic microstructure of Fe84Nb7B9 alloys observed by electron holographyJournal of Applied Physics, 2003
- Magnetic hardening and spin-glass phenomena in nanocrystalline FeNbB at low temperaturesPhysical Review B, 2001
- Random magnetocrystalline anisotropy in two-phase nanocrystalline systemsPhysical Review B, 1998
- Analysis of the dependence of spin-spin correlations on the thermal treatment of nanocrystalline materialsPhysical Review B, 1995
- Nanocrystalline Soft Magnetic Fe–M–B (M=Zr, Hf, Nb) Alloys Produced by Crystallization of Amorphous Phase (Overview)Materials Transactions, JIM, 1995
- Soft magnetic properties of nanocrystalline bcc Fe-Zr-B and Fe-M-B-Cu (M=transition metal) alloys with high saturation magnetization (invited)Journal of Applied Physics, 1991
- High Saturation Magnetization and Soft Magnetic Properties of bcc Fe–Zr–B and Fe–Zr–B–M (M=Transition Metal) Alloys with Nanoscale Grain SizeMaterials Transactions, JIM, 1991
- High Saturation Magnetization and Soft Magnetic Properties of bcc Fe–Zr–B Alloys with Ultrafine Grain StructureMaterials Transactions, JIM, 1990
- Fe-Based Soft Magnetic Alloys Composed of Ultrafine Grain StructureMaterials Transactions, JIM, 1990
- Grain size dependence of coercivity and permeability in nanocrystalline ferromagnetsIEEE Transactions on Magnetics, 1990