Three-state dual spin valve structure

Abstract

A dual spin valve is built with exchange bias on the top and bottom pinned layers and a central free layer. By suitable choice of the antiferromagnetic and ferromagnetic layer thicknesses, it is possible to separate the three magnetization switching fields and produce a staircase magnetoresistive curve. The maximum magnetoresistance ratio is 7.6% for currentperpendicular-to-plane and 6.3% for current-in-plane geometries with intermediate magnetoresistances of 3.9% and 3.0% respectively. The use of exchange bias in a multistate memory device is discussed.

Stretchable Spin Valve with Stable Magnetic Field Sensitivity by Ribbon-Patterned Periodic Wrinkles

“…, parallel to the exchange bias (the inset of Figure c). All samples show the typical dual spin valve GMR behaviors, where the GMR curves exhibit three resistance states due to the incoherent magnetic switching of the top and bottom pinned layers (indicated by arrows in Figure a) . The GMR ratios (Δ R / R 0 ) max of 9.8%, 10.2%, and 7.9% are obtained in the spin valves of SVR-0%, SVR-30%, and SVR-50%, respectively (Figure a–c).…”

“…All samples show the typical dual spin valve GMR behaviors, where the GMR curves exhibit three resistance states due to the incoherent magnetic switching of the top and bottom pinned layers (indicated by arrows in Figure 3a). 41 The GMR ratios (ΔR/R 0 ) max of 9.8%, 10.2%, and 7.9% are obtained in the spin valves of SVR-0%, SVR-30%, and SVR-50%, respectively (Figure 3a−c). The strain effect on the GMR performance of the wrinkled SVRs was measured by applying different tensile strains varying from a few percent to a few tens of percent parallel to the prestrain.…”

“…In this structure, the biaxial strain accompanying with stretching operation (the uniaxial applied tensile strain and the induced transverse compressive strain due to the Poisson effect) can be accommodated, thus significantly reducing the influence of the residual strain on the GMR performance. Moreover, we employ a dual spin valve structure, which has been demonstrated to show the higher GMR ratio and higher magnetic field sensitivity than those of the conventional simple spin valve because of the spin dependent scattering on the both sides of the free layer, − to construct the multilayer magnetic sensor. Different to the GMR multilayer-based magnetic sensor, the dual spin-valve sensor is appropriate for detecting weak field with high magnetic field sensitivity.…”

All‐Organic Dual Spin Valves with Well‐Resolved Four Resistive‐States

“…Even if these configurations were achieved with three FM materials, they did not offer four distinct resistive states, since the number of spin‐flip interfaces in C(↑↑↓) and C(↑↓↓) configurations still remained the same. The DSVs have hence resulted three resistive states with 0, 1, and 2 spin‐flip interfaces, even though Valet–Fert theory predicted four states . The other approach to achieve four resistive states in SVs was to use multiferroic materials having a voltage‐modulated polarization as the space layer …”