  This paper describes the observation of non-equilibrium field effects at room
temperature in four disordered insulating systems: granular Al, discontinuous
Au, amorphous NbSi and amorphous InOx thin films. The use of wide enough gate
voltage ranges and a cautious analysis of the data allow us to uncover memory
dips, the advocated hallmark of the electron glass, in the four systems. These
memory dips are found to relax slowly over days of measurements under gate
voltage changes, reflecting the impossibility for the systems to reach an
equilibrium state within experimentally accessible times. Our findings
demonstrate that these electrical glassy effects, so far essentially reported
at cryogenic temperatures, actually extend up to room temperature.
