Longitudinal and transverse magnetoresistances of YBa2Cu3O7 in very high field up to 430 kG

Measurements of the resistivity, together with the longitudinal and transverse magnetoresistances of YBa2Cu3O7 in extremely high fields up to 430 kG at different temperatures (4.2--300 K) are reported. It is shown that the application of a field as high as 430 kG does not destroy superconductivity at 50 K. Moreover the resistance at 77 K and 430 kG does not approach the saturation limit and is only --50% of that of the normal phase. A large negative and anisotropic magnetoresistance Δrho is observed at high temperatures (T>100 K). It is suggested that this behavior could be either of magnetic origin or due to some influence of the electromagnetic field on the short-range order of oxygen ions