The resistivity of single-crystal pentatellurides, HfTe 5 and ZrTe 5 , has been measured as a function of temperature and applied magnetic field. At zero magnetic field these materials exhibit a peak in their resistivity ͑at T P ) as a function of temperature that corresponds to an, as yet, undetermined phase transition. The application of a transverse magnetic field ͑B Ќ to the current I͒ has a profound effect on the resistive peak in these materials, shifting the peak to slightly higher temperatures and producing a large enhancement of the resistivity at the peak, up to a factor of 3 in ZrTe 5 (T P ϭ145 K͒ and 10 in HfTe 5 (T P ϭ80 K͒. Larger magnetoresistance is observed at even lower temperatures, TϽ20 K. ͓S0163-1829͑99͒06035-X͔

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The discharge characteristics of silver vanadium oxide (SVO) as a cathode in lithium-silver vanadium oxide (Li-SVO) primary battery was studied under various operating conditions. The cathode yielded a capacity of 260 mAh g )1 at a current density of 0.08 mA cm )2 , although the theoretical capacity of this material is 315 mAh g )1 . The pulse discharge characteristics were studied under conditions that simulate battery operation inside an implantable cardio-verter defibrillator (ICD). The variation of the ohmic resistance of the system was studied as a function of depth of discharge. Rate capability and impedance studies indicated high diffusion limitations for this system especially at high depth of discharge. Morphological changes during discharge were also discussed using scanning electron microscopic studies.

Electronic structure and thermoelectric properties of half-Heusler Zr0.5Hf0.5NiSn by first-principles calculationsThe thermoelectric properties ͑resistivity and thermopower͒ of single crystals of the low dimensional pentatelluride materials, HfTe 5 and ZrTe 5 , have been measured as a function of temperature from 10 KϽTϽ320 K. The effect of small amounts of Ti substitutional doping (M 1Ϫx Ti x Te 5 , where M ϭHf, Zr͒ on the thermoelectric properties is reported here. A resistive transition occurs in the pentatellurides, as evidenced by a peak in the resistivity, T P Ϸ80 K for HfTe 5 and T P Ϸ145 K for ZrTe 5 . Both parent materials exhibit a large positive ͑p-type͒ thermopower near room temperature which undergoes a change to negative ͑n-type͒ below the peak temperature. The thermal conductivity is relatively low ͑Ϸ5 W/m K͒ for the M Te 5 materials. The Ti substitution affects the electronic properties strongly, producing a substantial shift in the peak temperature while the large values of thermopower remain essentially unaffected. These results warrant further investigation of these materials as candidates for low temperature thermoelectric applications.