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Journal of Applied Physics -- April 15, 1997 -- Volume 81, Issue 8 pp. 5058-5060

Magnetic anisotropy, coupling, and transport in epitaxial Co/Cr superlattices on MgO(100) and (110) substrates

J. Johanna Picconatto and Michael J. Pechan

Department of Physics, Miami University, Oxford, Ohio 45056

Eric E. Fullerton

Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439

Superlattices of Co/Cr have been epitaxially sputtered onto MgO(100) and (110) substrates coated with epitaxial Cr(100) and (211) buffer layers. The Co thickness is fixed at 20 Å and the Cr thickness varied from 7 to 22 Å. On the MgO(110)/Cr(211) substrates, coherent hcp-Co(100)/bcc-Cr(211) superlattice structures are formed. On MgO(100)/Cr(100), x-ray-diffraction results suggest strained hcp-Co(11)/bcc-Cr(100) superlattices. Magnetization measurements show fourfold magnetic in-plane anisotropy for the MgO(100) orientation and twofold for the MgO(110). By utilizing a simple model based upon perpendicular uniaxial anisotropies, we have concluded that the fourfold anisotropy has its origin in the second-order uniaxial Co anisotropy energy. The antiferromagnetic interlayer coupling strength exhibits a maximum value of 0.15 erg/cm² at a Cr thickness of 13 Å in the MgO(110) orientation. The MgO(100) orientation exhibits its strongest coupling of 0.55 erg/cm³ at 10 Å Cr thickness. Modest giant magnetoresistance values no larger than 3% are observed and we find no evidence of enhanced anisotropic magnetoresistance effects recently reported for Co(100)/Cr(211) superlattices. ©1997 American Institute of Physics.

PII: S0021-8979(97)49508-7
DOI: 10.1063/1.364507
PACS: 75.70.Cn, 75.50.Cc, 75.50.Ee, 75.30.Gw, 68.35.Ct, 72.15.Gd, 75.70.Pa, 68.65.+g        Additional Information

Citing Articles

1. Magnetic properties of Co/Re hcp(100) superlattices
   T. Charlton et al., Phys. Rev. B 59, 11897 (1999)
2. Giant magnetoresistance in Fe_{1 – x}Co_x/Cr(001) trilayers
   C. T. Yu et al., Phys. Rev. B 57, 2955 (1998)
3. High coercivity, epitaxial Sm–Co films with uniaxial in-plane anisotropy
   Eric E. Fullerton et al., Appl. Phys. Lett. 71, 1579 (1997)