35 research outputs found
Growth modes of nanoparticle superlattice thin films
We report about the fabrication and characterization of iron oxide
nanoparticle thin film superlattices. The formation into different film
morphologies is controlled by tuning the particle plus solvent-to-substrate
interaction. It turns out that the wetting vs. dewetting properties of the
solvent before the self-assembly process during solvent evaporation plays a
major role to determine the resulting film morphology. In addition to layerwise
growth also three-dimensional mesocrystalline growth is evidenced. The
understanding of the mechanisms ruling nanoparticle self-assembly represents an
important step toward the fabrication of novel materials with tailored optical,
magnetic or electrical transport properties
Magnetic relaxation phenomena in the superspin-glass system [Co\u3csub\u3e80\u3c/sub\u3eFe\u3csub\u3e20\u3c/sub\u3e/Al\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e]\u3csub\u3e10\u3c/sub\u3e
Relaxation and temperature cycles of thermoremanent magnetization, MTRM, in the superspin-glass phase of [Co80Fe20 (0.9 nm)/Al2O3 (3 nm)] 10 have been investigated. The relaxation of MTRM exhibits ageing phenomena. In negative temperature cycles for temperature steps larger than 1 K the magnetic state is retrieved (memory effect) on returning to the measurement temperature. This property is independent of the application of a field step during intermediate cooling. In positive temperature cycles the relaxation is suppressed after temporary heating. The observations are discussed in the light of both the droplet and the hierarchical picture
Fractures of the anterior lateral edge of the distal tibia in adolescents after sports injury
Depth profile of uncompensated spins in an exchange bias system
We have used the unique spatial sensitivity of polarized neutron and soft x-ray beams in reflection geometry to measure the depth dependence of magnetization across the interface between a ferromagnet and an antiferromagnet. The net uncompensated magnetization near the interface responds to applied field, while uncompensated spins in the antiferromagnet bulk are pinned, thus providing a means to establish exchange bias