Ferroelasticity Bratkovsky et al., 1996

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

Characteristic hysteresis of ferroelastic materials Salje, 2000

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

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

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

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

Evolution of domain structures with time Salje, 2000

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

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

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

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

Nanotechnology Aird et al., 1998

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

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.

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, 101-103, 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.

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