TY - JOUR
T1 - Charge-density wave instability and nonlinear transport in Tl0.3MoO3 a new blue molybdenum oxide bronze
AU - Collins, B. T.
AU - Ramanujachary, K. V.
AU - Greenblatt, M.
AU - Waszczak, J. V.
N1 - Funding Information:
emu/g).8 This is due to the increased diamagnetism of thallium. The similarities of the structural and transport properties of T10_3MoO3 relative to K0.3Mo03 and RbO.3MoO3 suggest that a similar mechanism of transport is operative in all three systems. The nearly identical T, value=lose to 180K in each indicate that the electronic properties are determined primarily by the Moo6 octahedral network which is nearly the same in each bronze as evidenced by the almost identical values of the crystallographic b dimension (Table I). The I-V characteristics of T10.3Mo03 along the unique direction (b) show that the nonlinear behavior vanishes above 184K. as expected. The relatively higher threshold fields observed in T10.3MoO3 (300-400mV/cm), compared to.KO.3MoO3 where ET values as low as 30-50mV/cm were seen, is probably related to the higher concentration of impurities or defects in TlO.3MoO3 as discussed above. In all other cases it has been demonstrated that ET is related to the concentration of impurities and/or defects. The dielectric relaxation of CDW in TlO.3MoO3 has been characterized at temperatures 40-200K by the measurement of a frequency dependent AC conductivity between lOliz-1OMHx at different bias voltages. Preliminary analysis of these results show that qualitatively the AC conductivity is similar to that of K0_3MoO3,3~ NbSe335 and TaS3.35 However, at -77K the characteristic frequency of relaxation (1.2 x 106~2) is about two orders of magnitude larger than that of Kg.3MoO3 (-3 x 104Hz). The higher relaxation frequencies observed in TlO,3Mo03 corroborate the higher ET values observed in TlO.3MoO3 as further evidence of strong "pinning" centers in this bronze. In the temperature range studied, the relaxation times are observed to increase with temperture in an Arrhenius fashion. The results of the real conductivity as a function of finite applied bias indicate the relaxation of CDW below ET. Finally, we find that for bias above ET the behavior is no longer characteristic of dielectric relaxation.36 Acknowledgements -Useful discussions with F.J. DiSalvo is gratefully acknowledged. We thank Prof. J.A. Potenza for measuring the lattice parameters of the crystals, W.H. McCarroll for orienting a large single crystal of T10_3Mo03 by X-ray diffraction methods and R.A. Gerhardt for her help with the frequency dependent AC complex impedance measurement. Supported by National Science Foundation-Solid State Chemistry Grant DMR-84-04003.
PY - 1985/12
Y1 - 1985/12
N2 - Single crystals of Tl0.3MoO3 blue bronze were grown by the temperature gradient flux technique for the first time. Tl0.3MoO3 crystalizes with monoclinic symmetry, space group C2, C2/m or Cm, a = 18.486(1) A ̊, b = 7.5474(6) A ̊, c = 10.0347(7) A ̊, β = 118.377(6)° and appears to be isostructural with the K0.3MoO3 blue bronze. The physical properties of Tl0.3MoO3 are similar to those of the K3MoO3 and Rb3MoO3 phases. The resistivity of Tl0.3MoO3 is highly anisotropic and its temperature susceptibility (4.2-300K) decreases sharply with decreasing temperature near the transition seen in the resistivity. The onset of another transition <60K is also indicated by the susceptibility data. Non-linear current-voltage (I-V) characteristics observed at ∼70K above applied threshold voltages of the order of ∼300mV/cm suggest the sliding of charge density condensate.
AB - Single crystals of Tl0.3MoO3 blue bronze were grown by the temperature gradient flux technique for the first time. Tl0.3MoO3 crystalizes with monoclinic symmetry, space group C2, C2/m or Cm, a = 18.486(1) A ̊, b = 7.5474(6) A ̊, c = 10.0347(7) A ̊, β = 118.377(6)° and appears to be isostructural with the K0.3MoO3 blue bronze. The physical properties of Tl0.3MoO3 are similar to those of the K3MoO3 and Rb3MoO3 phases. The resistivity of Tl0.3MoO3 is highly anisotropic and its temperature susceptibility (4.2-300K) decreases sharply with decreasing temperature near the transition seen in the resistivity. The onset of another transition <60K is also indicated by the susceptibility data. Non-linear current-voltage (I-V) characteristics observed at ∼70K above applied threshold voltages of the order of ∼300mV/cm suggest the sliding of charge density condensate.
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U2 - 10.1016/0038-1098(85)90863-4
DO - 10.1016/0038-1098(85)90863-4
M3 - Article
AN - SCOPUS:0022233803
SN - 0038-1098
VL - 56
SP - 1023
EP - 1028
JO - Solid State Communications
JF - Solid State Communications
IS - 12
ER -