Determination of magnetostriction for spin-valve devices with 5.0 and 10.0 nm Permalloy layers

Abstract

The objective of this study is to determine the extent of magnetostriction in spin valves. Spin valves were fabricated on a silicon substrate using dc magnetron sputter deposition techniques with the following structure: Ta5.0/NiFe5.0 or 10.0/Co1.0/Cu3.0/Co3.0/Ru0.6/Co2.0/FeMn10.0/Ta5.0, where the subscripts denote the layer thickness in nanometers. The Permalloy composition used in these studies was Ni80Fe20. Spin valves were created in a serpentine shape to maximize the total magnetostriction (ΔL/L) by increasing the device length per die area. Device widths of between 1 and 40 μm with lengths of 1000–40 000 μm were fabricated. Devices were subjected to an external magnetic field while a mechanical force was applied to the backside of the substrate. An increase in the anisotropy field Hk, is observed with increasing stress. This increase is observed for all devices tested but is more distinct for those containing the 5.0 nm Permalloy. Results show that maximum magnetostriction occurs abruptly at lower stress values for the 10.0 nm Permalloy while magnetostriction for the 5.0 nm Permalloy occurs gradually over a wider range of stress values. Magnetoresistance measurements also show an inverse relationship between applied stress and (ΔR/R) performance. Magnetostriction analysis becomes critical as both device complexity and integration levels increase.

High-performance giant magnetoresistive sensorics on flexible Si membranes

“…This value is within the range of the figures previously reported for individual Ni-Fe thin films. 28,37 This strain induced effect is also reported for GMR multilayers prepared on flexible polymeric supports, 38 but are not observed when the GMR stacks are deposited onto pre-stretched elastomeric rubber membranes. 13,39 The latter is attributed to the formation of wrinkles, which accommodate tensile deformations of the substrate without straining the magnetic layers.…”

“…The maximum strain applied, estimated by considering purely geometrical factors, was 0.4%, which lies within the range that was estimated in other studies on thicker Si substrates. 26,37 By fitting the experimental data ( Fig. 3(b)) to Eq.…”

Electrodeposition of Serpentine CoCu/Cu Multilayered GMR Micro-device

“…The serpentine geometry has also been used in the development of a superconducting magnetic field sensor (10) for the same purpose of increasing resistance; and for detection of magnetostriction in a spin-valve as a way to increase the device length per unit area. (11).…”