TY - JOUR
T1 - Tin telluride
T2 - A weakly co-elastic metal
AU - Salje, E. K.H.
AU - Safarik, D. J.
AU - Modic, K. A.
AU - Gubernatis, J. E.
AU - Cooley, J. C.
AU - Taylor, R. D.
AU - Mihaila, B.
AU - Saxena, A.
AU - Lookman, T.
AU - Smith, J. L.
AU - Fisher, R. A.
AU - Pasternak, M.
AU - Opeil, C. P.
AU - Siegrist, T.
AU - Littlewood, P. B.
AU - Lashley, J. C.
PY - 2010/11/18
Y1 - 2010/11/18
N2 - We report resonant ultrasound spectroscopy (RUS), dilatometry/ magnetostriction, magnetotransport, magnetization, specific-heat, and S 119 n Mössbauer spectroscopy measurements on SnTe and Sn0.995 Cr 0.005 Te. Hall measurements at T=77K 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≤1100K, 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 0.5μm distortion at Tc ≈ 85K. Whereas our RUS measurements on SnTe show elastic hardening near the structural transition, pointing to co-elastic behavior, similar measurements on Sn0.995 Cr 0.005 Te show a pronounced softening, pointing to ferroelastic behavior. Effective Debye temperature, θD, values of SnTe obtained from S 119 n Mössbauer studies show a hardening of phonons in the range 60-115 K (θD =162K) as compared with the 100-300 K range (θD =150K). 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 Δ C44 / 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 ∼75K, 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.
AB - We report resonant ultrasound spectroscopy (RUS), dilatometry/ magnetostriction, magnetotransport, magnetization, specific-heat, and S 119 n Mössbauer spectroscopy measurements on SnTe and Sn0.995 Cr 0.005 Te. Hall measurements at T=77K 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≤1100K, 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 0.5μm distortion at Tc ≈ 85K. Whereas our RUS measurements on SnTe show elastic hardening near the structural transition, pointing to co-elastic behavior, similar measurements on Sn0.995 Cr 0.005 Te show a pronounced softening, pointing to ferroelastic behavior. Effective Debye temperature, θD, values of SnTe obtained from S 119 n Mössbauer studies show a hardening of phonons in the range 60-115 K (θD =162K) as compared with the 100-300 K range (θD =150K). 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 Δ C44 / 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 ∼75K, 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.
UR - http://www.scopus.com/inward/record.url?scp=78649698245&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.82.184112
DO - 10.1103/PhysRevB.82.184112
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AN - SCOPUS:78649698245
SN - 1098-0121
VL - 82
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 18
M1 - 184112
ER -