Aging and slow dynamics in SrxBa1-xNb2O6

The uniaxial "relaxor" ferroelectric SrxBa1-xNb2O6 (SBN) is found to crossover from holelike to cumulative aging as it is cooled into the frozen relaxor regime. The cumulative aging contrasts sharply with the behavior of cubic relaxors, supporting ideas that the spin-glasslike aging in cubic relaxors is connected with polarization components orthogonal to the net ferropolarization. In the relaxor regime, small dc fields are found to suppress much of the dissipative response, similar to long-time aging. Pyroelectric currents are measured, along with limits on pyroelectric noise, allowing limits to be set on dynamically coherent domain sizes. Large nonlinear susceptibilities are found near the freezing transition.