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Physical Review Letters -- November 30, 1998 -- Volume 81, Issue 22 pp. 4979-4982

Helical and Incommensurate Spin-Density Waves in Fe/Cr Multilayers with Interfacial Steps

R. S. Fishman

Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6032

(Received 28 May 1998)

Although absent in bulk transition metals, a noncollinear, helical (H) spin-density wave (SDW) is stabilized by steps at the interfaces in Fe/Cr multilayers. Using the random-phase approximation, we evaluate the phase boundary between the H SDW and the collinear, incommensurate (I) SDW found in bulk Cr. In agreement with neutron-scattering results, the I-to-H transition temperature T_IH is always lower than the bulk Néel temperature T_N and the nodes of the I SDW lie near the Fe-Cr interfaces. While a H SDW with a single ±/2 twist has lower free energy than a I SDW above T_N, H SDW's with larger twists are stable between T_IH and T_N. ©1998 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v81/p4979
PACS: 75.30.Fv, 75.30.Ds, 75.70.Cn        Additional Information

References

1. A. Schreyer et al., Europhys. Lett. 32, 595 (1995); [INSPEC] [ISI]
   Phys. Rev. Lett. 79, 4914 (1997).
   
2. P. Bödeker et al., Phys. Rev. Lett. 81, 914 (1998).
   
3. E. Fawcett, Rev. Mod. Phys. 60, 209 (1988); [SPIN]
   E. Fawcett et al., Rev. Mod. Phys. 66, 25 (1994). [SPIN] [ISI]
   
4. J. C. Slonczewski, J. Magn. Magn. Mater. 150, 13 (1995). [INSPEC] [ISI]
   
5. S. S. P. Parkin, N. More, and K. P. Roche, Phys. Rev. Lett. 64, 2304 (1990). [ISI]
   
6. M. Donath et al., Phys. Rev. B 43, 13 164 (1991). [ISI]
   
7. E. E. Fullerton, S. D. Bader, and J. L. Robertson, Phys. Rev. Lett. 77, 1382 (1996). [ISI]
   
8. S. Adenwalla et al., Phys. Rev. B 53, 2474 (1996). [ISI]
   
9. J. C. Slonczewski, Phys. Rev. Lett. 67, 3172 (1991). [ISI]
   
10. D. Stoeffler and F. Gautier, J. Magn. Magn. Mater. 121, 259 (1993). [INSPEC] [ISI]
    
11. Two sets of C SDW domains with polarizations 90° apart can also couple perpendicular Fe moments with Cr spins at z = 0 and L making 135° angles with their neighboring Fe moments. However, each C SDW will be twisted by the Fe moments, turning this spin configuration into the pair of H SDW's sketched in Fig. 1.
    
12. K. Hirai, J. Phys. Soc. Jpn. 65, 586 (1996). [INSPEC] [ISI]
    
13. A. W. Overhauser, Phys. Rev. Lett. 4, 462 (1960).
    
14. P. J. Brown et al., Proc. Phys. Soc. London 85, 1185 (1965).
    
15. W. M. Lomer, Proc. Phys. Soc. London 80, 489 (1962).
    
16. P. A. Fedders and P. C. Martin, Phys. Rev. 143, 8245 (1966).
    
17. R. S. Fishman and S. H. Liu, Phys. Rev. B 48, 3820 (1993). [ISI]
    
18. R. S. Fishman (unpublished).
    
19. A. Shibitani, K. Motizuki, and T. Nagamiya, Phys. Rev. 177, 984 (1969). [INSPEC]
    
20. R. S. Fishman and S. H. Liu, Phys. Rev. Lett. 76, 2398 (1996). [ISI]
    
21. Z. P. Shi and R. S. Fishman, Phys. Rev. Lett. 78, 1351 (1997); [ISI]
    R. S. Fishman and Z. P. Shi, J. Phys. C 10, L277 (1998). [INSPEC] [ISI]
    
22. J. Unguris, R. J. Celotta, and D. T. Pierce, Phys. Rev. Lett. 67, 140 (1991); [ISI]
    69, 1125 (1992).
    
23. Relaxing this approximation and allowing the angle between neighboring Cr and Fe moments to deviate from 180° lowers the IH transition temperature slightly but does not affect any of our conclusions.
    
24. R. S. Fishman, Phys. Rev. B 57, 10 284 (1998). [ISI]
    
25. E. E. Fullerton et al., Phys. Rev. Lett. 75, 330 (1995). [ISI]
    

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