3. History
Theory developed in 1971 by professor LEON
CHUA at University of California, Berkeley.
Practical model developed in 2006 by R Stanley
Williams
Scientists at HP( Hewlett Packard ) Labs built the
first working memristor in 2008
4. Symmetry diagram showing the 6 distinct possible
realizations based on the four circuit variables
5.
6. Why not discovered yet?
Memristor are usually very small in size and therefore they
are not able to be identified until the recent birth of Nano
electronics and the corresponding study of charge transport
in solid-state.
8. Observations
There is change in resistance depending on flow of charge
Resistance increase when charge flow in one direction and decrease
when flow in another
When applied voltage is switched off charge flow will get stopped but
when flow of charge starts again the device remember its last resistance
(resistance equal to value at which it was last active)
It cant be replaced by any other combination
10. The first memristor
Cross-section of the first HP TiO2-
memristor consisting of
a high conductive (doped) and a low
conductive (undoped) part
placed in between two platinum
electrodes. The boundary
between the two parts is dynamic and
is moved back and forth by
the passing charge carriers. The
parameter w(t) is a mathematic
variable that describes the position of
this boundary
11. M(q)=R1+R2
M(q)=R1+R2=Roff (1-kRon/D² q(t))
Roff -high resistance
Ron-low resistance
K-constant
D-length of the memristor in the direction of the
charge flow
q(t) - electric charge passing through the
memristor as a function of time
w-work done by memristor
12. A useful water analogy
A-low resistivity(high conductivity)
a-high resistivity(low resistivity)
Pipe model of a memristor
13. There are two layer one is slightly
depleted(reduced) of oxygen atom and
another other is non depleted
Depleted layer had much lower
resistance then non depleted
16. i-v characteristics
The memristance of the memristor depends
on the amount of electric charge that has
passed through the device.
Current is nonlinear with the applied
voltage, resulting in hysteresis loops rather
than straight lines.
If the signal frequency, ω, is sufficiently
high, the memristance of the memristor has
too little time to respond to the passing
charge, resulting in the collapse of the
hysteresis loops to straight lines.
Behaviour of memristor----------------------
17. Basic memristor properties
An ac element, not dc
No storage of energy
Two-point terminal circuit element
Pinched hysteresis loop in the i-v plane
Nonlinear q-φ curve
Low-frequency property and frequency-dependent
memristance
Typically only apparent at small scales.
21. Conclusion
The rich hysteresis v-I characteristics detected in many thin film
devices can now be understood as memristor
Memristor is a fundamental circuit element
It take lots of transistor and capacitor to do the job of a single
memristor
No combination of R,L,C circuit can duplicate memristor
