Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Direct evidence for a half-metallic ferromagnet

Abstract

Half-metallic materials are characterized by the coexistence of metallic behaviour for one electron spin and insulating behaviour for the other. Thus, the electronic density of states is completely spin polarized at the Fermi level, and the conductivity is dominated by these metallic single-spin charge carriers. This exotic physical property could have a significant effect on technological applications related to magnetism and spin electronics. Some ferromagnetic systems, such as Heusler compounds1 and chromium dioxide2, have been predicted theoretically to be half-metallic. However, a half-metallic system has not been demonstrated directly and the predictions are still in doubt3,4. Here we report spin-resolved photoemission measurements of a ferromagnetic manganese perovskite, La0.7Sr0.3MnO3, which directly manifest the half-metallic nature well below the Curie temperature. For the majority spin, the photoemission spectrum clearly shows a metallic Fermi cut-off, whereas for the minority spin, it shows an insulating gap with disappearance of spectral weight at 0.6 eV binding energy.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: High-resolution photoemission spectra of a thin film of La 0.7Sr0.3MnO3, very near the Fermi energy (EF).
Figure 2: Spin-resolved photoemission spectra of a thin films of La 0.7Sr0.3MnO3 (asin Fig. 1), near the Fermi energy (EF).
Figure 3: Schematic energy diagrams and the Mn 3d spin alignments of the doped manganese perovskites at T TC and at T > TC.

References

  1. de Groot, R. A., Muller, F. M., van Engen, P. G. & Buschow, K. H. J. New class of materials: half-metallic ferromagnets. Phys. Rev. Lett. 50, 2024–2027 (1983).

    ADS  CAS  Article  Google Scholar 

  2. Schwarz, K. CrO2 predicted as a half-metallic ferromagnet. J. Phys. F 16, L211–L215 (1986).

    ADS  CAS  Article  Google Scholar 

  3. Bona, G. L., Meier, F., Taborelli, M., Bucher, E. & Schmidt, P. H. Spin polarized photoemission from NiMnSb. Solid State Commun. 56, 391–394 (1985).

    ADS  CAS  Article  Google Scholar 

  4. Kämper, K. P., Schmitt, W., Güntherodt, G., Gambin, R. J. & Ruf, R. CrO2 — a new half-metallic ferromagnet? Phys. Rev. Lett. 59, 2788–2791 (1988).

    ADS  Article  Google Scholar 

  5. Hanssen, K. E. H. M., Mijnarends, P. E., Rabou, L. P. L. M. & Buschow, K. H. J. Positron-annihilation study of the half-metallic ferromagnet NiMnSb: experiment. Phys. Rev. B 42, 1533–1540 (1990).

    ADS  CAS  Article  Google Scholar 

  6. Jonker, G. H. & van Santen, J. H. Ferromagnetic compounds of manganese with perovskite structure. Physica 16, 337–349 (1950).

    ADS  CAS  Article  Google Scholar 

  7. Tokura, Y. et al. Giant mangetotransport phenomena in filling-controlled Kondo lattice system: La1−xSrxMnO3. J. Phys. Soc. Jpn 63, 3931–3935 (1994).

    ADS  CAS  Article  Google Scholar 

  8. von Helmholt, R., Wecker, J., Holszapfel, B., Schultz, L. & Samwer, K. Giant negative magnetoresistance in perovskitelike La2/3Ba1/3MnOx ferromagnetic films. Phys. Rev. Lett. 71, 2331–2334 (1993).

    ADS  Article  Google Scholar 

  9. Jin, S. et al. Thousandfold change in resistivity in magnetoresistive La-Ca-Mn-O films. Science 264, 413–415 (1994).

    ADS  CAS  Article  PubMed  Google Scholar 

  10. Zener, C. Interaction between the d-shells in the transition metals. II. Ferromagnetic compounds of manganese with perovskite structure. Phys. Rev. 82, 403–405 (1951).

    ADS  CAS  Article  Google Scholar 

  11. Millis, A. J., Shraiman, B. I. & Mueller, R. Dynamic Jahn–Teller effect and colossal magnetoresistance in La1−xSrxMnO3. Phys. Rev. Lett. 77, 175–178 (1996).

    ADS  CAS  Article  PubMed  Google Scholar 

  12. Park, J.-H. et al. Electronic aspects of the ferromagnetic transition in manganese perovskites. Phys. Rev. Lett. 76, 4215–4218 (1996).

    ADS  CAS  Article  PubMed  Google Scholar 

  13. de Teresa, J. M. et al. Evidence for magnetic polarons in the magnetoresistive perovskites. Nature 386, 256–258 (1997).

    ADS  Article  Google Scholar 

  14. Okimoto, Y. et al. Anomalous variation of optical spectra with spin polarization in double exchange ferromagnet: La1−xSrxMnO3. Phys. Rev. Lett. 75, 109–112 (1995).

    ADS  CAS  Article  PubMed  Google Scholar 

  15. Hwang, H. Y., Cheong, S.-W., Ong, N. P. & Batlogg, B. Spin-polarized intergrain tunneling in La2/3Sr1/3MnO3. Phys. Rev. Lett. 77, 2041–2044 (1996).

    ADS  CAS  Article  PubMed  Google Scholar 

  16. de Boer, P. K., van Leuken, H., de Groot, R. A., Rojo, T. & Barberis, G. E. Electronic structure of La0.5Ca0.5MnO3. Solid State Commun. 102, 621–626 (1997).

    ADS  CAS  Article  Google Scholar 

  17. Pickett, W. E. & Singh, D. J. Electronic structure and half-metallic transport in the La1−xCaxMnO3system. Phys. Rev. B 53, 1146–1160 (1996).

    ADS  CAS  Article  Google Scholar 

  18. Lu, Y. et al. Large magnetotunneling effect at low magnetic fields in micrometer-scale epitaxial La0.67Sr0.33MnO3tunnel junctions. Phys. Rev. B 54, R8357–R8360 (1996).

    ADS  CAS  Article  Google Scholar 

  19. Sun, J. Z., Krusin-Elbaum, L., Duncombe, P. R., Gupta, A. & Laibowwitz, R. B. Spin-polarized tunneling in doped perovskite manganate trilayer junctions. Appl. Phys. Lett. 70, 1769–1771 (1997).

    ADS  CAS  Article  Google Scholar 

  20. Kwon, C. et al. Stress-induced effects in epitaxial (La0.7Sr0.3)MnO3films. J. Magn. Magn. Mater. 172, 229–236 (1997).

    ADS  CAS  Article  Google Scholar 

  21. Vescovo, E. et al. The U5UA SGM-beamline: First Tests on the Performances A-25 (Activity Rep. 1996, National Synchrotron Light Source, Brookhaven National Lab, Upton, 1997).

    Google Scholar 

  22. Sarma, D. D. et al. Temperature-dependent photoemission spectral weight in La0.6Sr0.4MnO3. Phys. Rev. B 53, 6873–6877 (1996).

    ADS  CAS  Article  Google Scholar 

  23. Saitoh, T. et al. La1−xSrxMnO3studied by photoemission and X-ray absorption spectroscopy. Phys. Rev. B 51, 13942–13951 (1995).

    ADS  CAS  Article  Google Scholar 

  24. Trajanovic, Z. et al. Growth of colossal magnetoresistance thin films on silicon. Appl. Phys. Lett. 69, 1005–1007 (1996).

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We thank J. Hastings for discussions. NSLS is supported by the US Department of Energy; the work in the University of Maryland was partially supported by the US Office of Naval Research.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to J.-H. Park.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Park, JH., Vescovo, E., Kim, HJ. et al. Direct evidence for a half-metallic ferromagnet. Nature 392, 794–796 (1998). https://doi.org/10.1038/33883

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/33883

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing