Skip to main content Accessibility help

Microstructural Study of CMR Films as a Function of Growth Temperature, As-Deposited and Annealed

  • M. E. Hawley (a1), X. D. Wu (a2), P. N. Arendt (a3), C. D. Adams (a3), M. F. Hundley (a4) and R. H. Heffner (a4)...


The properties encompassed by the family of complex metal oxides span the spectrum from superconductors to insulating ferroelectrics. Included in this family are the new colossal magnetoresistive perovskites with potential applications in advanced high density magnetic data storage devices based on single or multilayer thin films units of these materials fabricated by vapor phase deposition (PVD) methods. The realization of this potential requires solving basic thin film materials problems requiring understanding and controlling the growth of these materials. Toward this end, we have grown La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3 on LaAlO3 single crystal substrates by pulsed laser and RF sputter deposition at temperatures from 500° C to 900° C and annealed at over 900° C for about 10 hours. The evolution of the microstructure of these films was studied by scanning probe microscopies and transmission electron microscopy (TEM).

The results of SPM characterization showed that at the lower end of the growth temperature range, the as-grown films were polygranular with grain size increasing with temperature. The 500° C as-grown films appeared to be amorphous while the 750° C film grains were layered with terrace steps often one unit cell high. In contrast, films grown at 900° C consisted of coalesced islands with some 3-D surface crystals. After annealing, all films had coalesced into very large extended layered islands. The change in microstructure was reflected in a decreased resistivity of coalesced films over their unannealed granular precursors. Previous reported work on the growth of La0.84 Sr0.16MnO3 and La0.8Sr0 2CoO3 grown demonstrated the sensitivity of the microstructure to substrate and deposition conditions. Films grown on an “accidental” vicinal surface grew by a step flow mechanism.



Hide All
1. Raistrick, I. D., and Hawley, M. E., “Scanning Tunneling and Atomic Force Microscope Studies of Thin Sputtered Films of YBa2Cu3O7”, in Interface in High Temperature Superconductors, eds. Shinde, Subhash and Rudman, David A., chapter 2, p. 28 (Springer-Verlag, NY, NY, 1993).
2. Brosha, E.L., Chung, B.W.,, Garzon, F.H., Raistrick, I.D., Houlton, R.J., and Hawley, M.E., J. Electrochem. Soc. 142 (5), 1702 (1995).
3. Chung, B.W., Brosha, E.L., Garzon, F.H., Raistrick, I.D., Houlton, R.J., and Hawley, M.E., J. Mat. Res. 10(10), 2518 (1995).
4. von Helmolt, R., Wecher, J., Holzapfel, B., Schultz, L., and Samwer, K., Phys. Rev. Lett. 71,2331 (1993).
5. Jin, S., Tiefel, T.H., McCormack, M., Fastnacht, R.A., Ramesh, R., and Chen, L.H., Science 264, 413 (1994).
6. Ju, H.L., Kwon, C., Li, Q., Greene, R.L., and Venkatesan, T., Appl. Phys. Lett. 65, 108 (1994).
7. Schiffer, P., Ramirez, A.P., Bao, W., and Cheong, S-W., preprint.
8. Hundley, M.F., Hawley, M., Heffner, R.H., Jia, Q.X., Neumeier, J.J., Tesmer, J., Thompson, J.D., and Wu, X.D., Appi. Phys. Lett. 67(6), 860 (1995).
9. Hundley, M.F., unpublished measurement.


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed