The exchange bias coupling at ferromagnetic/antiferromagnetic interfaces in epitaxially grown Co/CoO layers can intentionally be increased by a factor of up to 3 if the antiferromagnetic CoO layer is diluted by nonmagnetic defects in its volume part away from the interface. Monte Carlo simulations of a simple model of a ferromagnetic layer on a diluted antiferromagnet show exchange bias and explain qualitatively its dilution and temperature dependence. These investigations reveal that diluting the antiferromagnet leads to the formation of volume domains, which cause and control exchange bias.

We report on the first systematic study of spin transport in bilayer graphene (BLG) as a function of mobility, minimum conductivity, charge density and temperature. The spin relaxation time τ s scales inversely with the mobility µ of BLG samples both at room temperature (RT) and at low temperature (LT). This indicates the importance of D'yakonov -Perel' spin scattering in BLG. Spin relaxation times of up to 2 ns at RT are observed in samples with the lowest mobility. These times are an order of magnitude longer than any values previously reported for single layer graphene (SLG). We discuss the role of intrinsic and extrinsic factors that could lead to the dominance of D'yakonov-Perel' spin scattering in BLG. In comparison to SLG, significant changes in the carrier density dependence of τ s are observed as a function of temperature.

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An overview of one-and two-dimensional quantum spin systems based on transition-metal oxides and halides of current interest is given, such as spinPeierls, spin-dimer, geometrically frustrated and ladder systems. The most significant and outstanding contributions of magnetic light scattering to the understanding of these materials are discussed and compared to results of other spectroscopies and thermodynamic measurements.