Injection and Scattering of Polarized Spins at Nanoscale Polymer Interfaces
Abstract
We made excellent progress several directions. We demonstrated that V[TCNE]~2 is a room temperature fully spin polarized magnetic semiconductor of interest for spintronic applications, including spin valves. We increased the coercivity (which is crucial for spintronics device) of the parent material V[TCNE]~2 by doping with ions that have large magnetocrystalline anisotropy (Co, Fe, etc.). For Co and Fe substantially higher coercive fields, Hc, than the pure V[TCNE]2 (275 Oe for x = 0.3 and 1100 Oe for x = 0.05 at 5 K, respectively) were realized, while in case of Ni Hc does not exceed 14 Oe. Tc for the materials with x > 0.3 exceeds 300 K. We extended MR measurements to very high magnetic fields (up to 32 T) to observe the remarkable linear MR behavior below the ordering temperature predicted for this magnetic semiconductor. Ferrimagnetic resonance (FMR) studies have been performed on V[TCNE]~2 using high frequency microwaves (240 GHz) to enhance the spectral resolution. Effective magnetization, Meff, intensity and linewidth behaviors of individual peaks indicate long-range magnetic ordering and also the presence of glassy nature due to the formation of multi-domains. XANES studies performed at ANL, show that vanadium ions are coordinated by 6 nitrogen atoms.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 2004
- Accession Number
- ADA470558
Entities
People
- Arthur J. Epstein
Organizations
- Ohio State University