TRANSPORT-PROPERTIES OF SINGLE-CRYSTAL HGBA2CA2CU3O8+DELTA

We report the first measurements of the transport properties of single crystals of HgBa2Ca2Cu3O8+delta. Data for the in-plane and out-of-pla ne resistivity, in-plane Hall coefficient and in-plane thermoelectric power of single crystals with onset temperatures as high as 134 K are presented. The in-plane resistivity, Hall coefficient and thermoelectr ic power all indicate that these crystals are underdoped, which may of fer at least a partial explanation for the strong pressure dependence of T-c observed in this compound. The in-plane Hall coefficient shows a strong temperature dependence in accord with other cuprate supercond uctors. A calculation of the cotangent of the Hall angle (cot theta(H) ) reveals that the relation cot theta(H)=AT(2)+B is obeyed to high pre cision in these crystals, despite strong curvature of the in-plane res istivity. Data are also reported for the influence of magnetic field o n the resistive transition, for fields of up to 7 T applied both paral lel and perpendicular to the crystallographic c-axis. These latter mea surements give an estimate for the anisotropy of H-c2, implying a valu e which is intermediate between that found for YBa2Cu3O7-delta and Bi2 Sr2CaCu2O8+x.