Exchange bias in spin-engineered double superlattices

Exchange bias has been observed in sputtered magnetic double superlattices which consist of a ferromagnetically coupled superlattice grown on an antiferromagnetically (AF) coupled superlattice. This system exhibits a parallel domain wall, a spin flop transition, and exchange bias when the anisotropy is large in the AF block. This work shows that neither the domain wall nor the spin flop are directly related to exchange bias but that the anisotropy is essential.     

Identification of a novel series of alkylitaconic acids in wood cultures of Ceriporiopsis subvermispora by gas chromatography/mass spectrometry.

A novel series of long-chain unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid has been identified by gas chromatography/mass spectrometry during in vitro decay of eucalypt wood by the white-rot basidiomycete Ceriporiopsis subvermispora. The major compounds were identified as tetradecyl-, 7-hexadecenyl- and hexadecylitaconic acids by their mass fragmentation patterns. Other members of the same compound series, identified as dodecanyl-, tridecanyl-, tetradecenyl-, pentadecanyl-, octadecenyl- and octadecanylitaconic acids, were present in very minor amounts or traces. Whereas hexadecenylitaconic acid has already been reported in cultures of C. subvermispora, to our knowledge this is the first report of the presence of the other alkylitaconic acids in fungal cultures. These new alkylitaconic-type metabolites may constitute a source for peroxidizable lipids involved in lignin degradation during wood decay by C. subvermispora and other white-rot basidiomycetes.     

Direct experimental evidence for the Ruderman-Kittel-Kasuya-Yosida interaction in rare-earth metals

We show that the ferromagnetic heavy rare-earth (RE) metals show a transport spin polarization at the Fermi level in the majority spin, whereas in ferromagnetic light rare earths it is in the minority spin. The sign of the polarization is in agreement with what is expected due to the Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling formalism. We show that magnetotransport measurements on magnetic multilayer samples containing magnetic REs provide a unique opportunity to verify the RKKY coupling scheme in pure rare-earth metals, allowing us to probe both the sign and temperature dependence of the spin-density oscillation.     

Quenching of giant hysteresis effects in La(1-z)Y(z)Hx switchable mirrors

Hydrogen atoms adsorbed on TiO2(110)-(1x1) surfaces have been characterized by scanning tunneling microscopy (STM) combined with electron stimulated desorption (ESD) technique. Certain amounts of H atoms are unexpectedly found on the TiO2 surfaces annealed at 900 K. Two forms of adsorption were discriminated in STM images from the different sensitivity to ESD and tentatively assigned to hydroxyl-type (O-H) and hydride-type (Ti-H) species.     

Interface induced uniaxial magnetic anisotropy in amorphous CoFeB films on AlGaAs(001)

We demonstrate an isolated magnetic interface anisotropy in amorphous CoFeB films on (Al)GaAs(001), similar to that in epitaxial films but without a magnetocrystalline anisotropy term. The direction of the easy axis corresponds to that due to the interfacial interaction proposed for epitaxial films. We show that the anisotropy is determined by the relative orbital component of the atomic magnetic moments. Charge transfer is ruled out as the origin of the interface anisotropy, and it is postulated that the spin-orbit interaction in the semiconductor is crucial in determining the magnetic anisotropy.