Evidence of resistive switching into a dynamical state in antiferromagnetic iridates

We investigate the electrically-driven switching between low and high resistance states in antiferromagnetic Sr3Ir2O7 single crystals. We demonstrate that the switching state at high electrical biases displays an increased noise pattern, which is indicative of a dynamical state at high biases. We employ a spectrum analyzer to characterize the noise pattern associated with the high-bias switching state and investigate the dependence of the noise spectrum on the magnitude of applied bias and magnetic field. The emergence of the noise was found to be strongly correlated with the onset of resistive switching. The noise power density displayed a 1/f2 frequency dependence with an amplitude mimicking the hysteretic behavior of the resistance switching. We argue that the observed noise spectrum could be associated with a random switching between different states at high biases and discuss various interpretations of its origin including random telegraph signal (RTS) and red noises.