High-accuracy magnetostriction measurements in nickel structures using atomic force microscope

High-accuracy measurements of magnetomechanical displacements in various nickel structures used to obtain nanocontacts have been carried out on a atomic force microscope combined with an electromagnet. It was found that for Ni microwires fixed on a Cu substrate by pewter solder or by epoxy displacements under the magnetic field changing from 0 to 250 Oe are mainly due to magnetostriction. The same experiments for Ni films electrodeposited onto Cu substrates or evaporated onto MgO substrates within the experimental sensitivity (2 nm) showed no displacements. Therefore film structures with high adhesion to substrate most suitable for obtaining ballistic magnetoresistive nanocontacts. Positive and negative magnetoresistance was registered on Ni microwires fixed on a Cu substrate by pewter solder. However the form of the magnetoresistive curve in such structure couldn't be explained only by magnetostriction.