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Investigation of temperature power law dependence in the normal state magneto-resistivity of BSCCO

The normal state magneto-transport properties of the cuprates, like many of their other properties, are anomalous. The ab-plane resistivity is frequently linear for optimally doped samples while the Hall coefficient varies strongly with temperature and the inverse Hall angle, cot(Q), generally varies as T2, though often deviating from this at low temperatures. A range of theoretical models attempt to account for these observations. The most widely known include Anderson's early model[1] in which two separate scattering times govern the transverse and longitudinal scattering, a single strongly k dependent relaxation term such as that in NAFL models[2] and the use of charge conjugation symmetries to produce two relaxation times[3]. A recent study carried out into the magnetoresistance (MR) and Hall angle of Zn doped YBCO[4] produced some interesting results that prompted the current work. As has been reported previously, films with and without Zn were observed to strongly violate Kohler’ s law implying that the relaxation time is indeed k dependent. The current study on pure and 2% Fe and 2% Co doped BSCCO single crystals is being carried out to determine if a similar T-4 power law is present in this system, and if so, how it depends upon doping. To date, pure and Fe doped BSCCO single crystals, both near optimal doping, have had MR measurements performed. The crystals were produced by G. Balakrishnan using the travelling solvent floating zone method and have hole doping levels of p~0.19 as determined by the Tc of the pure crystal (Tc=83K). Thermo-power measurements have suggested that Fe and Co doping only has a very small effect on hole concentration, so p should be similar. [1] Anderson P. W. Anderson, Phys. Rev. Lett. 67, 2092 (1991) [2] B. P. Stojkovic and D. Pines, Phys. Rev. Lett. 76, 811 (1996) [3] P. Coleman, A. J. Schofield, and A. M. Tsvelik, Phys. Rev. Lett. 76, 1324 (1996) [4] I. Kokanović et al, Phys. Rev. B, 73, 184509 (2006)

High Tc superconductors; Magnetoresistivity; Hall coefficient; Thermo-power

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