Electronics

Memristor

A resistor that remembers how much charge went through it. Push current one way and the conducting layer grows, push it back and it shrinks, stop and it stays where you left it. Drive it with a sine and the I–V curve is a loop pinched at the origin.

Each dot is an oxygen vacancy you can count; the boundary between the halves is the device's entire memory

Resistance right now—

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Source

Drive it yourself 0.00 V

drag me up and down

Frequency 1.00 Hz

slow, fat loopfast, thin loop

R_on (fully doped) —

R_off (fully undoped) —

Film thickness D 10 nm

Ion mobility µ_v —

sluggisheager

Boundary

Time rate 1.0×

Values

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What to observe

Push the drive up and the vacancies drift, the doped layer grows and the resistance falls. Drop it back to zero and the boundary stays where you left it: the resistance is a record of the charge pushed through.
On AC the current-voltage curve is a loop pinched at the origin. Since v = M·i with M finite, zero current means zero voltage, a shape no resistor, capacitor or inductor can draw.
Raise the frequency and the loop collapses towards a line: the boundary has no time to move within a cycle, so M barely changes and it acts like a plain resistor.
Hit it with pulses big enough to slam the boundary into the walls. It latches between R_on and R_off, which is what makes it a memory cell.

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