Detection of magnetization inhomogeneities in ultra-scaled magnetic nanowires

Method for nonperturbative detection of one or more magnetic inhomogeneities resulting from nano-defects in a longitudinal magnetic sample structure possessing a shape-induced anisotropy and having a widest nanometric cross-sectional dimension from 1 nm to 500 nm, or from 1 nm to 50 nm comprising:

• a) movably positioning a sensing surface of a solid-state lattice sensor of diamond material, comprising one single spin defect (NV) in the apex of the solid-state lattice sensor, at a first scanning position in proximity of the magnetic sample structure,
• b) irradiating the one spin defect (NV) by applying optical radiation (L) and a microwave field continuously or in one or more pulses to the one spin defect (NV) such as to detect a Zeeman shift upon exposure of the irradiated one spin defect to the magnetic field of the magnetic sample structure,
• c) detecting a photoluminescence (PL) output signal from the solid-state lattice sensor comprising the one spin defect (NV),
• d) scanning the surface of the magnetic sample structure in performing steps a) to c) at a series of scanning positions over at least a portion of the length of the magnetic sample structure such as to obtain quantitative information on the magnetic field spatial distribution,
• wherein an optically detected magnetic resonance (ODMR) spectrum is recorded at each of said scanning positions.