3 research outputs found
Palmer-Chalker correlations in the XY pyrochlore antiferromagnet Er2Sn2O7
\ersn\, is considered, together with \erti, as a realization of the XY
antiferromagnet on the pyrochlore lattice. We present magnetization
measurements confirming that \ersn\, does not order down to 100 mK but exhibits
a freezing below 200 mK. Our neutron scattering experiments evidence the strong
XY character of the \er moment and point out the existence of short range
correlations in which the magnetic moments are in peculiar configurations, the
Palmer-Chalker states, predicted theoretically for an XY pyrochlore
antiferromagnet with dipolar interactions. Our estimation of the \ersn\,
parameters confirm the role of the latter interactions on top of relatively
weak and isotropic exchange couplings
Change of cobalt magnetic anisotropy and spin polarization with alkanethiolates self-assembled monolayers
International audience; We demonstrate that the deposition of a self-assembled monolayer of alkanethiolates on a 1 nm thick cobalt ultrathin film grown on Au(111) induces a spin reorientation transition from in-plane to out-of-plane magnetization. Using ab initio calculations, we show that a methanethiolate layer changes slightly both the magnetocrystalline and shape anisotropy, both effects almost cancelling each other out for a 1 nm Co film. Finally, the change in hysteresis cycles upon alkanethiolate adsorption could be assigned to a molecular-induced roughening of the Co layer, as shown by STM. In addition, we calculate how a methanethiolate layer modifies the spin density of states of the Co layer and we show that the spin polarization at the Fermi level through the organic layer is reversed as compared to the uncovered Co. These results give new theoretical and experimental insights for the use of thiol-based self-assembled monolayers in spintronic devices