Large, linear c-axis magnetoresistance in YBa2Cu3O7-delta

Underdoped YBa2Cu3O7-delta Single crystals exhibit a large, positive c-axis magnetoresistance that is strikingly linear over a wide magnetic field ran ge up to 60 T. This linear magnetoresistance is observed at temperatures ne ar or below T-c, once sufficient magnetic field has been applied to suppres s superconductivity. The measurements are done in the longitudinal geometry , with current and magnetic field both along the c-axis (I\\B\\c). The line ar magnetoresistance can be large, giving as much as a 35% increase in resi stance between 30 T and 60 T. It also exhibits very strong temperature depe ndence, increasing by as much as an order of magnitude as the temperature i s reduced from 100 K to 10 K.