Abstract:

Dc resistivity of a zero-field cooled YBCO was previously studied as a function of angle between applied field and transport current. The resistivity followed a sin2q variation that was understood as a consequence of Lorentz force like effect. The resistivity deviated from the harmonic curve giving a minimum at low angles before following the true sin2q behavior. The angle corresponding to minimum voltage qmin has been thoroughly studied in this paper as a function of applied field, transport current and temperature. sin2q behavior of resistivity is not affected by the fields below Hc1 at their respective temperatures. The angle qmin reduces with increasing fields and vanishes at about fields of 8 kOe for 77K. qmin also decreases with increasing values of current and temperature when studied under constant externally applied field. The data are explained as a consequence of Lorentz force-mediated flux re-distribution in the inter- and intragranular regions which further support the idea of controversial Lorentz force-like dissipation. Key Word: Polycrystalline YBCO, dc resistivity, angular dependence, Lorentz force-like effect.

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