We report resonant ultrasound spectroscopy (RUS), dilatometry/magnetostriction, magnetotransport, magnetization, specific-heat, and 119Sn Mössbauer spectroscopy measurements on SnTe and Sn0.995Cr0.005Te. Hall measurements at T=77 K indicate that our Bridgman-grown single crystals have a p-type carrier concentration of 3.4×1019 cm−3 and that our Cr-doped crystals have an n-type concentration of 5.8×1022 cm−3. Although our SnTe crystals are diamagnetic over the temperature range 2≤T≤1100 K, the Cr-doped crystals are room-temperature ferromagnets with a Curie temperature of 294 K. For each sample type, three-terminal capacitive dilatometry measurements detect a subtle 0.5 μm distortion at Tc≈85 K. Whereas our RUS measurements on SnTe show elastic hardening near the structural transition, pointing to co-elastic behavior, similar measurements on Sn0.995Cr0.005Te show a pronounced softening, pointing to ferroelastic behavior. Effective Debye temperature, θD, values of SnTe obtained from 119Sn Mössbauer studies show a hardening of phonons in the range 60–115 K (θD=162 K) as compared with the 100–300 K range (θD=150 K). In addition, a precursor softening extending over approximately 100 K anticipates this collapse at the critical temperature and quantitative analysis over three decades of its reduced modulus finds ΔC44/C44=A|(T−T0)/T0|−κ with κ=0.50±0.02, a value indicating a three-dimensional softening of phonon branches at a temperature T0∼75 K, considerably below Tc. We suggest that the differences in these two types of elastic behaviors lie in the absence of elastic domain-wall motion in the one case and their nucleation in the other.
Physical Review B
Salje EKH, Safarik DJ, Modic KA, et al. Tin telluride: A weakly co-elastic metal. Physical Review B. 2010;82(18). doi:10.1103/physrevb.82.184112
Salje, E. K. H., Safarik, D. J., Modic, K. A., Gubernatis, J. E., Cooley, J. C., Taylor, R. D., … Lashley, J. C. (2010). Tin telluride: A weakly co-elastic metal. Physical Review B. APS. https://doi.org/10.1103/physrevb.82.184112
Salje, E. K. H., D. J. Safarik, Kimberly A Modic, J. E. Gubernatis, J. C. Cooley, R. D. Taylor, B. Mihaila, et al. “Tin Telluride: A Weakly Co-Elastic Metal.” Physical Review B. APS, 2010. https://doi.org/10.1103/physrevb.82.184112.
E. K. H. Salje et al., “Tin telluride: A weakly co-elastic metal,” Physical Review B, vol. 82, no. 18. APS, 2010.
Salje EKH, Safarik DJ, Modic KA, Gubernatis JE, Cooley JC, Taylor RD, Mihaila B, Saxena A, Lookman T, Smith JL, Fisher RA, Pasternak M, Opeil CP, Siegrist T, Littlewood PB, Lashley JC. 2010. Tin telluride: A weakly co-elastic metal. Physical Review B. 82(18), 184112.
Salje, E. K. H., et al. “Tin Telluride: A Weakly Co-Elastic Metal.” Physical Review B, vol. 82, no. 18, 184112, APS, 2010, doi:10.1103/physrevb.82.184112.