B J Hickey | Searcharxiv

arXiv2026

Probing frustrated metallo-molecular spin Kondo lattice interfaces through anomalous Nernst effect

Frustrated Kondo spin lattice (KSL) systems away from the antiferromagnetic (AFM) ground state have been found to display strange metal behaviour. A signature of strange metals in correlated systems is large Nernst response. Metallo-molecular interfaces of supramolecular lattices have been demonstrated as 2D KSL systems in STM studies. Here going beyond STM experiments we report a frustrated AFM state on molecular interfaces of Pt(111) and Pt(111)/Co films with around room temperature spin freezing transitions. Near these transitions we measure an anomalous Nernst coefficient of at least 3 $μ$V/K.

cond-mat.str-el↗

arXiv2025

Low-energy, ultrafast spin reorientation at competing hybrid interfaces with tunable operating temperature

Information can be stored in magnetic materials by encoding with the direction of the magnetic moment of elements. A figure of merit for these systems is the energy needed to change the information rewrite the storage by changing the magnetic moment. Organic molecules offer a playground to manipulate spin order, with metallo molecular interfaces being a promising direction for sustainable devices. Here, we demonstrate a spin reorientation transition in molecular interfaces of high magnetisation 3d ferromagnetic films due to a competition between a perpendicular magnetic anisotropy (PMA) induced by a heavy metal that dominates at high temperatures, and an in-plane anisotropy generated by molecular coupling at low temperatures. The transition can be tuned around room temperature by varying the ferromagnet thickness (1.4 to 1.9 nm) or the choice of molecular overlayer, with the organic molecules being C60, hydrogen and metal (Cu, Co) phthalocyanines. Near the transition temperature, the magnetisation easy axis can be switched with a small energy input, either electrically with a current density of 10^5 A per cm2, or optically by a fs laser pulse of fluence as low as 0.12 mJ per cm2, suggesting heat assisted technology applications. Magnetic dichroism measurements point toward a phase transition at the organic interface being responsible for the spin reorientation transition.

cond-mat.mes-hall↗