Quench-cooling procedure compared with the gate protocol for aging experiments in electron glasses

Anderson-insulating indium-oxide films excited far from equilibrium exhibit a variety of memory effects including aging. Full-aging has been recently demonstrated in this system using two different experimental protocols. The first, (gate-protocol) employed a MOSFET structure and involved switching between two gate voltages. In a different procedure, the system was subjected to a non-ohmic longitudinal field F for a waiting-time tw, and the relaxation of G was monitored after the field was switched back to its linear response value. In this paper we describe yet another protocol that involves measuring the response of the system that has been "aged" at some low temperature TL for a duration tw after it was quench-cooled from high temperature TH. As in the previous protocols, this procedure results in full-aging behavior. The advantages and shortcomings of the quench-cooling protocol are pointed out. The results of aging experiments based on the better-controlled, gate-protocol performed with different systems are compared and discussed.