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The computer bits are binary, with a value of 0 or 1. In contrast, brain neurons can have all kinds of different internal states, depending on the input received. This allows the brain to process information in a more energy-efficient way than a computer. Physicists at the University of Groningen (UG) are working on memristors, niobium-doped strontium titanate memory resistors, which mimic the function of neurons. Their results were published in the Journal of Applied Physics October 21st.
The brain is superior to traditional computers in many ways. Brain cells use less energy, process information faster and are more adaptable. The way brain cells respond to a stimulus depends on the information received, which potentiates or inhibits neurons. Scientists are working on new types of devices, called memristors, capable of reproducing this behavior.
Memory
Researcher UG Anouk Goossens, the first author of the article, tested memristors made from niobium-doped strontium titanate. The conductivity of the memristors is controlled analogically by an electric field: "We use the ability of the system to switch a resistor: by applying voltage pulses, we can control the resistance and, with the help of a low voltage, read the current in different states. . The strength of the pulse determines the resistance in the device. We have shown that a resistance level of at least 1000 is achievable. We then measured what happened over time. Goossens was particularly interested in the temporal dynamics of states of resistance.
She observed that the duration of the impulse with which the resistance was set determined the duration of the "memory". This can last from one to four hours for pulses of one second to two minutes. In addition, she found that after 100 switching cycles, the material showed no sign of fatigue.
Oversight
"There are different things you can do with that," says Goossens. "In" learning "the device in different ways, using different impulses, we can change his behavior." The fact that resistance changes over time can also be helpful: "These systems can forget just like the brain. This allows me to use time as a variable parameter. In addition, devices manufactured by Goossens combine memory and processing in a single device, which is more efficient than traditional computer architecture in which storage (on magnetic hard disk) and processing (in the CPU) are separated. .
Goossens conducted the experiments described in this article during a research project as part of the Master of Nanoscience program at the University of Groningen. The Goossens research project took place within the group of students supervised by Dr. Tamalika Banerjee of the spintronics of functional materials. She is now a student doctoral student in the same group.
Questions
Before building brain-like circuits with his device, Goossens intends to conduct experiments to fully understand what is happening in the material. "If we do not know exactly how it works, we will not be able to solve any problem that may occur in these circuits. We must therefore understand the physical properties of the material: what is it and why? & # 39;
The questions that Goossens wants to answer include the parameters that influence the states reached. "And if we make 100 of these devices, do they all work the same way? If they do not do it and there is variation between devices, this should not be a problem. After all, all the elements of the brain are not identical.
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