The possibility of combining ultra-thin magnetic and non-magnetic layers has led in particular to the discovery of the giant magnetoresistance (GMR) and to the development of experiments in the current-perpendicular to the plane (CPP) geometry.

More recently, technical progress in lithography has enabled the creation of nanodevices in which the lateral dimension is smaller than characteristic physical lengths such as the "spin diffusion length". Thus, the effects usually observed in CPP configurations can now be observed in "lateral" devices in which the current flows in the plane of the wafer and no longer perpendicularly.

Researchers at the Inac were able to make "lateral" spin valves with which they measured GMR variations of more than 10%. This result is as good as in a CPP configuration!

The scientists emphasize that the geometries of the magnetic and non-magnetic parts can be freely tailored, leaving room for the imagination. It is therefore possible to create multilevel memory with high spin signals through manipulating the geometry of the lateral structures, by controlling the coercivity and shape anisotropy of the magnetic parts.

The Inac team also studied a new device comprising a nanodisk in which the direction of magnetization can be detected. They have established that controlling the magnetic properties now makes it possible to take advantage of all the spin degrees of freedom, which are usually obscured in CPP devices.

Thanks to the flexibility of these structures, it is now possible to use spin-orbit effects to create and detect spin accumulations, or even spin-transfer pairs to switch magnetizations.