On the nature of giant magnetoresistance in a ferromagnet-polymer-nonmagnetic metal system

The role of magnetostriction in manifestations of the giant magnetoresistance (GMR) in a nickel-poly(arylenephthalide)-copper system has been studied. It is established that the appearance (disappearance) of GMR at the nickel-polymer interface is not correlated with a significant change in magnetostrictive deformations, since the transverse and longitudinal magnetostriction in the substrate plane remains almost unchanged in the entire interval of magnetic fields inducing the transition. The role of the longitudinal magnetostriction perpendicular to the sample plane cannot be considered as determining, since the same sample exhibits a change in the sign of the conductivity switching depending on the initial conditions for the same sign of the longitudinal magnetostriction in the substrate. The possibility of controlling the GMR threshold field by changing the applied bias voltage is also not indicative of the influence of magnetostriction on this phenomenon.