Lecturer: Dr. Amos Sharoni
Affiliation: Department of Physics
& Institute of Nanotechnology
and Advanced Material, Bar-Ilan University
Abstract:
Transition metal oxides (TMOs) are complex
electronic systems which exhibit a multitude
of collective phenomena. Two archetypal
examples are VO2 and NdNiO3, which undergo
a metal-insulator phase-transition (MIT), the
origin of which is still under debate.
We have discovered a new kind of memory
effect in both systems, manifest through an
increase of resistance at a specific
temperature, which is set by reversing the
temperature-ramp from heating to cooling
during the MIT, thus we call it ‘Ramp Reversal
Memory’.
The characteristics of this memory effect do
not coincide with any previously reported
history or memory effects in similar systems.
From a broad range of experimental features,
supported by theoretical modelling, we claim
that the main ingredients for the effect to
arise are the spatial phase-separation of
metallic and insulating regions during the MIT
and the coupling of lattice strain to the local
critical temperature of the phase transition.
We predict that similar ramp-reversal effects
exist also in other systems.
* N. Vardi et. Al. “Ramp Reversal Memory
and Phase-Boundary Scarring in Transition
Metal Oxides”, under review.