Transverse voltage in zero external magnetic fields, its scaling and violation of the time-reversal symmetry in MgB2

Abstract The longitudinal and transverse voltages (resistances) have been measured for MgB 2 in zero external magnetic fields. Samples were prepared in the form of thin film and patterned into the usual Hall bar shape. In close vicinity of the critical temperature T c non-zero transverse resistance has been observed. Its dependence on the transport current has been also studied. New scaling between transverse and longitudinal resistivities has been observed in the form ρ xy ∼ d ρ xx /d T . Several models for explanation of the observed transverse resistances and breaking of reciprocity theorem are discussed. One of the most promising explanation is based on the idea of time-reversal symmetry violation.