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Tunnel junction based memristors as artificial synapses.

Thomas A, Niehörster S, Fabretti S, Shepheard N, Kuschel O, Küpper K, Wollschläger J, Krzysteczko P, Chicca E - Front Neurosci (2015)

Bottom Line: The low amplitudes of the resistance change in these types of junctions are the major obstacle for their use.Here, we increased the amplitude of the resistance change from 10% up to 100%.Utilizing the memristive properties, we looked into the use of the junction structures as artificial synapses.

View Article: PubMed Central - PubMed

Affiliation: Thin Films and Physics of Nanostructures, Bielefeld University Bielefeld, Germany ; IFW Dresden, Institute for Metallic Materials Dresden, Germany.

ABSTRACT
We prepared magnesia, tantalum oxide, and barium titanate based tunnel junction structures and investigated their memristive properties. The low amplitudes of the resistance change in these types of junctions are the major obstacle for their use. Here, we increased the amplitude of the resistance change from 10% up to 100%. Utilizing the memristive properties, we looked into the use of the junction structures as artificial synapses. We observed analogs of long-term potentiation, long-term depression and spike-time dependent plasticity in these simple two terminal devices. Finally, we suggest a possible pathway of these devices toward their integration in neuromorphic systems for storing analog synaptic weights and supporting the implementation of biologically plausible learning mechanisms.

No MeSH data available.


Related in: MedlinePlus

(A) Long-term potentiation and long-term depression of an MgO-based magnetic tunnel junction. The refreshed state is set to zero (green bars). The relative resistance increase is shown in blue and the relative resistance decrease in orange. (B) A cartoon of an example pulse sequence of 30 pulses. It consists of a series of 1 s rectangular pulses, convoluted by a sinusoidal half-wave with the amplitude vmax. The pulses are separated by 200 ms intervals. For similar pulse sequences, the pulse widths and pulse intervals are always fixed (1 s and 0.2 s, respectively) and the sine function involved in the convolution has a half-period given by the total duration of pulse sequence.
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Figure 3: (A) Long-term potentiation and long-term depression of an MgO-based magnetic tunnel junction. The refreshed state is set to zero (green bars). The relative resistance increase is shown in blue and the relative resistance decrease in orange. (B) A cartoon of an example pulse sequence of 30 pulses. It consists of a series of 1 s rectangular pulses, convoluted by a sinusoidal half-wave with the amplitude vmax. The pulses are separated by 200 ms intervals. For similar pulse sequences, the pulse widths and pulse intervals are always fixed (1 s and 0.2 s, respectively) and the sine function involved in the convolution has a half-period given by the total duration of pulse sequence.

Mentions: The resistance change of the MgO junctions is determined by a number of voltage pulses, leading to a relative change in resistance as depicted in Figure 3A. First, we will look into one example, where a pulse sequence of 30 voltage pulses is used, which corresponds to the bars of Figure 3A marked with digits i and 1–4. The pulse sequence itself is described by the cartoon in Figure 3B and is inspired by biological data (Rose and Dunwiddie, 1986). The initial state is indicated by the green bar marked with an i.


Tunnel junction based memristors as artificial synapses.

Thomas A, Niehörster S, Fabretti S, Shepheard N, Kuschel O, Küpper K, Wollschläger J, Krzysteczko P, Chicca E - Front Neurosci (2015)

(A) Long-term potentiation and long-term depression of an MgO-based magnetic tunnel junction. The refreshed state is set to zero (green bars). The relative resistance increase is shown in blue and the relative resistance decrease in orange. (B) A cartoon of an example pulse sequence of 30 pulses. It consists of a series of 1 s rectangular pulses, convoluted by a sinusoidal half-wave with the amplitude vmax. The pulses are separated by 200 ms intervals. For similar pulse sequences, the pulse widths and pulse intervals are always fixed (1 s and 0.2 s, respectively) and the sine function involved in the convolution has a half-period given by the total duration of pulse sequence.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493388&req=5

Figure 3: (A) Long-term potentiation and long-term depression of an MgO-based magnetic tunnel junction. The refreshed state is set to zero (green bars). The relative resistance increase is shown in blue and the relative resistance decrease in orange. (B) A cartoon of an example pulse sequence of 30 pulses. It consists of a series of 1 s rectangular pulses, convoluted by a sinusoidal half-wave with the amplitude vmax. The pulses are separated by 200 ms intervals. For similar pulse sequences, the pulse widths and pulse intervals are always fixed (1 s and 0.2 s, respectively) and the sine function involved in the convolution has a half-period given by the total duration of pulse sequence.
Mentions: The resistance change of the MgO junctions is determined by a number of voltage pulses, leading to a relative change in resistance as depicted in Figure 3A. First, we will look into one example, where a pulse sequence of 30 voltage pulses is used, which corresponds to the bars of Figure 3A marked with digits i and 1–4. The pulse sequence itself is described by the cartoon in Figure 3B and is inspired by biological data (Rose and Dunwiddie, 1986). The initial state is indicated by the green bar marked with an i.

Bottom Line: The low amplitudes of the resistance change in these types of junctions are the major obstacle for their use.Here, we increased the amplitude of the resistance change from 10% up to 100%.Utilizing the memristive properties, we looked into the use of the junction structures as artificial synapses.

View Article: PubMed Central - PubMed

Affiliation: Thin Films and Physics of Nanostructures, Bielefeld University Bielefeld, Germany ; IFW Dresden, Institute for Metallic Materials Dresden, Germany.

ABSTRACT
We prepared magnesia, tantalum oxide, and barium titanate based tunnel junction structures and investigated their memristive properties. The low amplitudes of the resistance change in these types of junctions are the major obstacle for their use. Here, we increased the amplitude of the resistance change from 10% up to 100%. Utilizing the memristive properties, we looked into the use of the junction structures as artificial synapses. We observed analogs of long-term potentiation, long-term depression and spike-time dependent plasticity in these simple two terminal devices. Finally, we suggest a possible pathway of these devices toward their integration in neuromorphic systems for storing analog synaptic weights and supporting the implementation of biologically plausible learning mechanisms.

No MeSH data available.


Related in: MedlinePlus