Transistorless Microchips

A group of electrical engineers at the University of Notre Dame have created a working prototype of a radical new chip design based on magnetism instead of electrical transistors.

History :
The potential of chips driven by nanoscale magnets was considered five years ago, scientists observed that the magnets could exchange information as their fields interacted with each other.

Although existing technologies use magnetic fields to store information on small chips called MRAMs, this is the first application to produce a chip that can process digital information in addition to storing it.

How it works :

The chip uses nanoscale magnetic "islands" to juggle the ones and zeroes of binary code.

It uses a process of magnetic patterning to produce a new chip that uses arrays of separate magnetic domains. Each island maintains its own magnetic field.

The magnets were created from ferromagnetic nickel/iron alloy, We evaporated a thin layer of the alloy onto a silicon surface, then patterned the islands using electron-beam lithography.

Advantages :

1. Computers using the magnetic chips would boot up almost instantly.
2. Because the chip has no wires, its device density and processing power may eventually be much higher than transistor-based devices.
3. And it won't be nearly as power-hungry, which will translate to less heat emission and a cooler future for portable hardware like laptops.
4. The magnetic chip's memory is nonvolatile, making it impervious to power interruptions, and it retains its data when the device is switched off.
5. The magnetic architecture of the chip can be reprogrammed on the fly and its adaptability could make it very popular with manufacturers of special-purpose computing hardware, from video-game platforms to medical diagnostic equipment.
6. The new chips also have some important characteristics that might make them ideal candidates for use in future space hardware. "You can't just put a regular DRAM into space, because it won't tolerate the environment. The magnetic technology is radiation-hard, and will be a huge improvement on what they're using now."

Indepth detail :

The chip's nanomagnets -- on the order of 110 nanometers wide -- can be assembled into arrays that mirror the function of transistor-based logic gates in addition to storing information. These logic gates are the building blocks of computer technology, giving microchips the power to process the endless rivers of binary code.

A NAND logic gate, for example, accepts two inputs to arrive at one output. If both inputs are one, the NAND gate spits out a zero. If one or the other or both inputs are a zero, the NAND gate provides a one as an output.

New chip works with a universal logic gate, a combination of the NAND and NOR gates. Together, these two logic gates can perform any of the basic arithmetic functions intrinsic to all computer processing.

Logic operations within the processor commence with a pulsed magnetic field on the input magnet, which alters the orientation of its magnetic field. This creates a cascade effect across the array, as magnetostatic attraction and repulsion cause the fields of adjacent magnets to "flip."

"To read the output, we used a scanning probe to infer what the magnetization was," said Porod. "Ideally, in the future, we would like to achieve this (input and output) with the simple application of an electric current."

Scanning electron microscope (or SEM) imagery shows the "magnetic islands" of a new chip design that are impervious to power loss.

A grouping of eight nanomagnets together are able to perform all mathematical calculations fundamental to Boolean logic.