Strain-controlled giant magnetoresistance of a spin valve grown on a flexible substrate

Abstract

This paper studies the strain-controlled giant magnetoresistance (GMR) change of a top pinned spin valve with the stacking structure of Co₉₀Fe₁₀/Cu/Co₉₀Fe₁₀/IrMn fabricated on a flexible polyethylene terephthalate substrate. The strain transverse to the magnetic easy axis can manipulate the magnetism of the Co₉₀Fe₁₀ layer and the Co₉₀Fe₁₀/IrMn bilayer and results in a large reversible and monotonic GMR variation from 0.64% (tensile strain) to 2.08% (compressive strain), which almost remains the same after bending 500 times. According to the Stoner–Wohlfarth model, the magnetic anisotropy of the free and pinned layers can be manipulated by strain, which causes the GMR variation of the spin valve. The heterostructure could also be used to generate a rectangle or sawtooth wave GMR signal. These findings indicate an efficient way to design magnetoelectric devices based on strain-modulated GMR changes.