1. Ferroelasticity
Bratkovsky et al., 1996

2. Background
Set
As T approaches the transition temperature, the shear modulus goes to zero and the material loses strength.

3. Characteristic hysteresis of ferroelastic materials
Salje, 2000

4. Spontaneous strain due to phase transitions
Yamada et al., 1992

5. Two possible phase transitions which lead
to the twin patterns of ferroelastic materials
Yamada et al., 1992

6. Extinction angles of two domains in a ferroelastic crystal
Nakayama et al., 1985

7. Tweed texture common in ferroelastic phase transitions
Bratkovsky et al., 1996

8. Evolution of domain structures with time
Salje, 2000

9. X-ray diffraction pattern for a twin wall
Salje, 2000

10. Mathematical Description of the Ferroelastic Material using Landau Theory
Locherer et al., 1996

11. Experimental results compared with theory
Bismayer et al., 1997
Chrosch et al., 1999
Chrosch et al., 1999
Chrosch et al., 1999

12. Applications
Ferroelastic materials could be useful for nanotechnology.
The behavior of natural minerals could be greatly influenced by their ferroelastic microstructures.

13. Nanotechnology
Aird et al., 1998

14. Geologic Impacts
Salje et al., 1998
Salje et al., 1998

15. Conclusions
The domain walls formed during ferroelastic phase transitions exhibit much different properties than the domains that they separate.
The properties of domains and their walls could be very useful in mineral physics and mineralogy research.

16. References
Aird, A., and Salje, E.K.H., 1998, J. Phys.: condens. matter, 10, L377.
Bismayer, U., Rower, R.W., Morgenroth, W., Guttler, B., 1997, Solid State Ionics, , 585.
Bratkovsky, A.M., Heine, V., Salje, E.K.H., 1996, Phil. Trans. R. Soc. Lond. A., 354, 2875.
Chrosch, J., and Salje E.K.H., 1999, J. Appl. Phys., 85, 722.
Locherer, K., Hayward, S., Hirst, P., Chrosch, J., Yeadon, M., Abell, J.S., and Salje, E.K.H., 1996, Phil. Trans. R. Soc. Lond. A., 354, 2815.
Nakayama, H., Ishii, K., Chijiwa, E., Wada, M., Sawada, A., 1985, Solid State Commun., 55, 59.
Salje, E.K.H., Gustaaf Van Tendeloo, A.B., Ishibashi, Y., Buckley, A., Nord, G.L., 1998, Am. Min, 83, 811.
Salje, E.K.H., 2000, Contemp. Phys., 41, 79.
Yamada, Y., and Uesu, Y., 1992, Solid State Commun., 81, 777.

17. Phase Transitions in Ferroelastic and Co-elastic Crystals By E. K
Phase Transitions in Ferroelastic and Co-elastic Crystals By E. K. Salje, Andrew Putnis, Robert C. Liebermann, Michael F. Hochella Jr
Thank You