Surface Plasmon Resonance from Bimetallic Interface in Au–Ag Core–Shell Structure Nanowires

Transverse surface plasmon resonances (SPR) in Au–Ag and Ag–Au core–shell structure nanowires have been investigated by means of quasi-static theory. There are two kinds of SPR bands resulting from the outer surface of wall metal and the interface between core and wall metals, respectively. The SPR corresponding to the interface, which is similar to that of alloy particle, decreases and shifts obviously with increasing the wall thickness. However, the SPR corresponding to the outer surface, which is similar to that of pure metal particle, increases and shifts slightly with increasing the wall thickness. A mechanism based on oscillatory surface electrons under coulombic attraction is developed to illuminate the shift fashion of SPR from bimetallic core–shell interface. The net charges and extra coulombic force in metallic wall affect the SPR energy and the shift fashion

Transition metal synthetic ferrimagnets: tuneable media for all optical switching driven by nanoscale spin current

All-optical switching of magnetization has great potential for use in future ultrafast and energy efficient nanoscale magnetic storage devices. So far, research was almost exclusively focused on rare-earth based materials, which limits device tunability and scalability. Here, we show that a perpendicularly magnetized synthetic ferrimagnet composed of two distinct transition metal ferromagnetic layers, Ni3Pt and Co, can exhibit helicity independent magnetization switching. Switching occurs between two equivalent remanent states with antiparallel alignment of the Ni3Pt and Co magnetic moments, and is observable over a broad temperature range. Time-resolved measurements indicate that the switching is driven by a spin-polarized current passing through the sub-nanometer Ir layer. The magnetic properties of this model system may be tuned continuously via sub-nanoscale changes in the constituent layer thicknesses as well as growth conditions, allowing the underlying mechanisms to be elucidated, and paving the way to a new class of data storage devices