​Various techniques exist for mapping magnetic fields, with various performances that are also complementary. One of them involves depositing a thin layer of magnetic nanoparticles on the surface to be analyzed, but it is not quantitative and also frequently alters the sample. So-called scanning methods, on the other hand, are more precise, but slower.

A team from INAC has proposed an optomechanic system built upon micro-electronic techniques. This system comprises a network of magnetic nanoribbons that are flexible and parallel to each other. Fixed to the substrate through one of their ends, the nanoribbons are free all along their length (overhung or cantilever) and they curve under the influence of a magnetic field. The optical observation of the nanoribbons field gives an image of the magnetic field spatial distribution. The action of a millimeter-sized permanent magnet is therefore visible to the naked eye, but field variations at a micronic scale can be visualized by optical microscopy.

By modulating the density and dimensions of these nanoribbons, it is possible to adapt the sensitivity and spatial resolution of the device.

The manufacturing processes were developed using equipment from the CEA Upstream Technological Platform (PTA).