A study of exchange bias in IrMn/Co systems is presented. Temperature and thickness dependence studies have revealed nonmonotonic behavior in both exchange bias fiel and coercivity with both variables. In particular the exchange bias fiel shows a peak for low IrMn thicknesses that is suppressed at temperatures higher than about 200 K. Calculations using the domain state model of exchange biasing are able to describe all the features seen in the experimental data.

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.

We design and investigate 11 different bis-oxoverdazyl diradicals connected by various aromatic couplers for their magnetic properties. The intramolecular magnetic exchange coupling constants (J) have been calculated using a broken symmetry approach in DFT framework. The J values are explained using spin polarization maps and magnetic orbitals. Isotropic hyperfine coupling constants (hfcc's) have been calculated for all the species in vacuum. The computed hfcc values also support intramolecular magnetic interactions. It has been found that some of the diradicals have ferromagnetic character while the others are antiferromagnetic in nature.

The occupation number and spatial position of the LUMO play an important role in magnetic exchange in diradicals.

Eric Clar's ideas concerning "aromatic sextets" are extended to a quantitative format in terms of a polynomial called the "Clar 2-nomial", along with related derivative quantities. The quantification is successfully tested to make correlations with a selection of numerical data, including resonance energies, bond lengths, and NICS ring-aromaticity values.