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Magnetic Coupling and Magnetorcsistance 2 . 2 Interlayer Coupling and Magnetoresistance in Multilayers
| Content Provider | Semantic Scholar |
|---|---|
| Author | Fert, Albert |
| Abstract | In metallic systems, exchange interactions are propagated by itinerant electrons and thus can be transmitted over relatively long distances. It follows that exchange interactions can couple magnetic layers through non-magnetic metallic layers. Although the possibility of exchange coupling across non-magnetic layers has been considered for a long time, it was only clearly identified in 1986 and characterized in rare earth based multilayers C2.461 and Fe/Cr structures C2.47, 481. In 1990 the interest of the interlayer exchange was increased by the discovery of unexpected long range oscillations in the variation of the exchange constant with the thickness of the spacer layers C2.491 and a large number of systems have been investigated during the following years. The interest of the exchange coupled multilayers has also been enhanced by the discovery of the giant magnetoresistance. Prior to the discovery there were reports of unusual magnetoresistive effects in layered structures C2.501, and in 1988 giant magnetoresistance effects were first clearly observed and characterized in anti-ferromagnetically coupled Fe/Cr systems C2.5 1, 521. The promises of these magnetoresistive effects for applications (magnetic sensors) have triggered a large number of experimental and theoretical works. Exchange and magnetoresistance properties of multilayers are also presented in Sect. 2.4 by Parkin, and the theoretical models of the interlayer exchange are reviewed in Sect. 2.1 by Hnrhaway. Here we review experimental results on interlayer exchange in Sect. 2.2.1. Section 2.2.2 is devoted to the theory of exchange and to the interpretation of experimental data, with special attention to the simple case of exchange through noble metals. Sections 2.2.3-5 are devoted to the magnetoresistance properties and focused on experiments in exchange coupled structures. We also review the theoretical models, and we discuss the current understanding of the mechanisms of magnetoresistance. Interlayer coupling between ferromagnetic transition-metal ultrathin films has been observed for a wide range of spacer materials: (i) antiferromagnetic E2.63-791. Oscillatory behavior has been reported in almost all cases. The exchange coupling per unit area between two ferromagnetic layers Fl and F2 is commonly expressed as (2.44) where MI and M2 are, respectively. the magnetizations of F1 and F2, bl2 the |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www1.mpi-halle.mpg.de/~bruno/publis/R_1994_1.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
