Microstructural and Magnetic Properties of Core-Shell Ni-Ce Nanocomposite Particles Assemblies
Abstract
Novel magnetic core-shell Ni-Ce nanocomposite particles (15-50 nm) are presented. SEM observation indicates a strongly ferromagnetic interacting order with chain-like features among Ni-Ce nanocomposite particle assemblies. Typical HREM image demonstrates that many planar defects (ie. stacking faults) exist in large Ni core zone (10-45 nm); the innermost NiCe alloy and outermost NiO oxide exist in the thin shell layers (3-5 nm). Nano-diffraction patterns show an indication of well-defined spots characteristic and confirm the nature of this core-shell nanocomposite particles. Superparamagnetic relaxation behavior above average blocking temperature (T(sub B) =170K) for Ni-Ce nanocomposite particles assemblies have been exhibited. This superparamagnetic behavior is found to be modified by interparticle interactions, which depending on the applied field; size distribution and coupling with the strong interparticle interaction. In addition, an antiferromagnetic order occurs with a Neel temperature T(sub N) of about 11K due to Ce ion magnetic order function. A spin-flop transition is also observed below T(sub N) at a certain applied field and low temperature.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2001
- Accession Number
- ADP011038
Entities
People
- J. A. Toledo
- M. J. Yacaman
- Xiang-cheng Sun