SEMINAR ON RACETRACK

1

RACETRACK A New Class of Memory The Future Of Computer

Memory Systems 'Racetrack' memory

could gallop past the hard disk

Would enable a device such as an MP3 player to store about half a million songs - or 3,500 films - and cost far less to produce.

Redefines the Architecture of Memory.

2

What is racetrack memory?3

Racetrack memory, so named because the data "races" around the wire "track“.

A U-shaped magnetic nanowire is embedded into a silicon chip. Magnetic domains are then moved along the wire by pulses of

polarised current. They are read by fixed sensors arranged in the silicon itself. By switching powerful magnetic fields on and off we are able to

rapidly create magnetic domains in a wire less than a micron wide made of Permalloy - a magnetic material made of iron and nickel that is often found in disk drives.

These regions contains many magnetic atoms all aligned in the same direction and are separated by domain walls – thin regions where the atoms change their magnetic orientation from one alignment to the other

These can then be moved using much shorter nanoscale pulses. Future hard drives could store data by designating a domain wall

to be a binary one, while its absence could be interpreted as a binary zero,

The Technology4

“racetrack memory,” a technology that makes it possible to read and write data far faster than is possible with existing storage devices.

Unlike conventional memory, which relies on electronic charges to store data, Racetrack uses the spin of an electron.

Idea is to stand billions of ultrafine wire loops around the edge of a silicon chip — hence the name racetrack — and use electric current to slide infinitesimally small magnets up and down along each of the wires to be read and written as digital ones and zeros

The tiny magnets slides along the notched nanowires at speeds greater than 100 meters a second. Since the tiny magnetic domains have to travel only submolecular distances, it is possible to read and write magnetic regions with different polarization as quickly as a single nanosecond — far faster than existing storage technologies.

The need is to take microelectronics completely into the third dimension and thus explode the two-dimensional limits of Moore’s Law, the 1965 observation by Gordon E. Moore, a co-founder of Intel, that decrees that the number of transistors on a silicon chip doubles roughly every 18 months.

5 Fig:- OVERVIEW OF RACETRACK MEMORY ORGANISATION

BASED ON THE TECHNOLOGY OF :6

Spintronics (a neologism for "spin-based electronics"), also known as magnetoelectronics, is an emerging technology which exploits the quantum spin states of electrons as well as making use of their charge state.

Magnetoresistive Random Access Memory (MRAM) which is a non-volatile computer memory (NVRAM) technology, Unlike conventional RAM chip technologies, in MRAM data is not stored as electric charge or current flows, but by magnetic storage elements. The elements are formed from two ferromagnetic plates, each of which can hold a magnetic field, separated by a thin insulating layer. One of the two plates is a permanent magnet set to a particular polarity, the other's field will change to match that of an external field. A memory device is built from a grid of such "cells”.

Spintronics 7

Technology makes use of the spin state of electrons. In order to make a spintronic device, the primary requirement

is to have a system that can generate a current of spin polarized electrons, and a system that is sensitive to the spin polarization of the electrons.

The simplest method of generating a spin-polarised current is to inject the current through a ferromagnetic material.

The most common application of this effect is a giant magnetoresistance (GMR) device.

Spintronic plates are used in the field of mass-storage devices; in 2002 IBM scientists announced that they could compress massive amounts of data into a small area, at approximately one trillion bits per square inch.

The most successful spintronic device to date is the spin valve, due to their widespread application in harddisk read/write heads.

MRAM-Magnetoresistive Random Access

Memory 8

A memory device is built from a grid of such "cells". Reading is accomplished by measuring the electrical resistance of the

cell. A particular cell is (typically) selected by powering an associated transistor which switches current from a supply line through the cell to ground.

By measuring the resulting current, the resistance inside any particular cell can be determined, and from this the polarity of the writable plate. Typically if the two plates have the same polarity this is considered to mean "0", while if the two plates are of opposite polarity the resistance will be higher and this means "1".

Proposed uses for MRAM include devices such as: Aerospace and military systems Digital cameras Notebooks Smart cards Mobile telephones Cellular base stations Personal Computers

MRAM CELL9

How it works ?10

Racetrack uses spin-coherent electric current to move the magnetic domains along an U-shaped nanoscopic wire.

As current is passing through the wire, the domains move over the magnetic read/write heads positioned at the bottom of the U, which alter the domains to record patterns of bits.

A memory device is made up of many such wires and read/write elements.

In general operational concept, racetrack memory is similar to the earlier twistor memory or bubble memory of the 1960s and 70s, but uses much smaller magnetic domains and dramatic improvements in magnetic detection capabilities to provide far higher areal densities.

Racetrack has neither of these problems. Reading and writing is fairly symmetrical and is limited primarily by the time it takes for the magnetic pattern to be moved across the read/write heads.

PROSPECTS11

Racetrack memory could blur the line between storage and computing, providing a key to a new way to search for data, as well as store and retrieve data.

It will not only change the way we look at storage, but it could change the way we look at processing information. We’re moving into a world that is more data-centric than computing-centric.

“racetrack memory,” could outpace both solid-state flash memory chips as well as computer hard disks, making it a technology that could transform not only the storage business but the entire computing industry.

It allow every consumer to carry data equivalent to a college library on small portable devices.

A tenfold or hundredfold increase in memory would be disruptive enough to existing storage technologies that it would undoubtedly unleash the creativity of engineers who would develop totally new entertainment, communication and information products.

THANKS…….12