Giant Magnetoresistance at Low Fields in Discontinuous NiFe-Ag Multilayer Thin Films

• Published in: Science (American Association for the Advancement of Science) Vol. 261; no. 5124; pp. 1021 - 1024
• Main Authors: Hylton, T. L., Coffey, K. R., Parker, M. A., Howard, J. K.
• Format: Journal Article
• Language: English
• Published: United States American Society for the Advancement of Science 20.08.1993; American Association for the Advancement of Science
• Subjects: Alloys; Anisotropy; Annealing; Grain boundaries; Magnetic fields; Magnetic materials; Magnetic properties; Magnetization; Magnetostatic fields; Magnetostatics; Room temperature; Thin films
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.261.5124.1021

A series of sputtered multilayers of Ni$_{80}$Fe$_{20}$-Ag was prepared to examine the giant magnetoresistance effect before and after annealing. For a wide range of NiFe and Ag thicknesses, no giant magnetoresistance was observed in the unannealed films. After annealing, a large, negative magnetoresistance was observed of order 4 to 6% in applied fields of order 5 to 10 oersteds at room temperature. The appearance of giant magnetoresistance is concurrent with the breakup of the NiFe layers, which is attributable to a magnetostatic interaction that favors local antiparallel alignment of the moments in adjacent layers. These structures may be of significant practical importance as sensors that require large changes in resistance at low fields, such as magnetoresistive heads used in magnetic recording systems.