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Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices and Enhanced Magnetoresistance in Layered Magnetic Structures with Antiferromagnetic Interlayer Exchange

Baibich Article Link

Binasch Article Link

Baibich, M.N., Broto, J.M., Fert, A., Nguyen Van Dau, F., Petroff, F., Eitenne, P., Creuzet, G., Friederich, A. & Chazelas, J., 1988. Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices. Phys. Rev. Lett. 61, 2472 and Binasch, G., Grünberg, P., Saurenbach, P., & Zinn W., 1989. Enhanced Magnetoresistance in Layered Magnetic Structures with Antiferromagnetic Interlayer Exchange. Phys. Rev. B 39, 4828

Essay about these articles

By the middle of 1986, the ingredients for producing a change in resistivity in a material by altering the magnetic background, i.e., producing giant magnetorsistance, were ready. As we eventually learned two groups knew and acted independently on this. Peter Grünberg at the KFA in Jülich, Germany, who was a pioneer in creating metallic multilayers and had experience in electrical transport measurements and Albert Fert, at the Université de Paris-Sud, who validated Mott’s two current model in ferromagnetic metals and was waiting for the propitious moment for a material to appear that allowed him to alter the magnetization.

Fert discussed his ideas with his former student, Alain Friederich, who was at Thomson-CSF (not far from Orsay, where Fert had his lab at the University). Thomson had, among other things, a molecular beam epitaxy (MBE) machine that allowed the researchers to grow Fe/Cr multilayers of nearly crystalline quality. To obtain a large change in the resistance with reorientation of the magnetic configuration, Fert chose to repeat the basic Fe/Cr motif between 30 and 60 times, which is a superlattice when one ignores boundary corrections. Interestingly Peter Grünberg chose another route; he grew a Fe/Cr/Fe trilayer.

Both discovered the GMR effect in 1988, albeit the manifestations were different. Fert achieved a large effect, of the order of 50%, to which he gave the name: Giant Magnetoresistance, however he needed about 2 tesla (magnetic field) to achieve this. Whereas Grünberg found an effect of the order 1.5% by using only 0.03 tesla. These differences were readily understood. One Fe/Cr/Fe trilayer is the minimum needed for GMR; repeating this motif a number of times amplifies its magnitude. As the number of repeats increases so does the magnitude of the GMR. However, this saturates as the thickness of the multilayer approaches the mean free path of the electrons. The external field necessary to effect the change is proportional primarily to strength of the exchange coupling between the iron layers.

Both groups were careful to show that this new phenomenon, GMR, is unrelated to anisotropic magnetoresistance (AMR), which is the change of resistance with the angle between the magnetization and direction of an external field. AMR is due to changes in the scattering cross section of electrons arising from reorienting the orbital charge cloud around atoms relative to the current direction; it is dependent on the spin-orbit coupling between the orbital and spin components of the magnetization. As this coupling is small in the transition-metals, the AMR is quite small. For the Fe/Cr trilayer studied by Grünberg, see Figure 2d of Binasch & Grunberg, et al. 1989, the AMR ratio was a few percent of the GMR ratio.

The above article is reprinted with permission from the author(s) of M. N. Baibich , J. M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Eitenne, G. Creuzet, A. Friederich, and J. Chazelas, Phys. Rev. Lett. 61, 2472 (1988) and G. Binasch, P. Grünberg, P. Saurenbach, & W. Zinn, Phys. Rev. B 39, 4828 (1988) Copyright (1988) and (1989) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.

Discussion Question

What are the different scientific versus technological impacts between the two discoveries of GMR?

Select articles citing these papers

Baibich 1988

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Chung, J. H., S. J. Chung, et al. (2008). "Carrier-Mediated Antiferromagnetic Interlayer Exchange Coupling in Diluted Magnetic Semiconductor Multilayers Ga1-xMnxAs/GaAs:Be." Physical Review Letters 101(23).

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Jin, S., T. H. Tiefel, et al. (1994). "THOUSANDFOLD CHANGE IN RESISTIVITY IN MAGNETORESISTIVE LA-CA-MN-O FILMS." Science 264(5157): 413-415.

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Binasch 1989

Guo, Z. B., Y. H. Wu, et al. (2008). "Exchange bias and magnetotransport properties in IrMn/NiFe/FeMn structures." Physical Review B 78(18).

Fert, A. (2008). "The present and the future of spintronics." Thin Solid Films 517(1): 2-5.

Chung, J. H., S. J. Chung, et al. (2008). "Carrier-Mediated Antiferromagnetic Interlayer Exchange Coupling in Diluted Magnetic Semiconductor Multilayers Ga1-xMnxAs/GaAs:Be." Physical Review Letters 101(23).

Zutic, I., J. Fabian, et al. (2004). "Spintronics: Fundamentals and applications." Reviews of Modern Physics 76(2): 323-410.

Sinova, J., D. Culcer, et al. (2004). "Universal intrinsic spin Hall effect." Physical Review Letters 92(12).

Valet, T. and A. Fert (1993). "THEORY OF THE PERPENDICULAR MAGNETORESISTANCE IN MAGNETIC MULTILAYERS." Physical Review B 48(10): 7099-7113.

Parkin, S. S. P., R. Bhadra, et al. (1991). "OSCILLATORY MAGNETIC EXCHANGE COUPLING THROUGH THIN COPPER LAYERS." Physical Review Letters 66(16): 2152-2155.

Dieny, B., V. S. Speriosu, et al. (1991). "GIANT MAGNETORESISTANCE IN SOFT FERROMAGNETIC MULTILAYERS." Physical Review B 43(1): 1297-1300.

Parkin, S. S. P., N. More, et al. (1990). "OSCILLATIONS IN EXCHANGE COUPLING AND MAGNETORESISTANCE IN METALLIC SUPERLATTICE STRUCTURES - CO/RU, CO/CR, AND FE/CR." Physical Review Letters 64(19): 2304-2307.

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