The document discusses spintronics, a nanotechnology that utilizes the spin-dependent properties of electrons for data storage and manipulation, offering advantages such as low power consumption, faster speeds, and non-volatility. It highlights the failure of Moore's Law as a driving factor for advancing spintronic technology and details devices like MRAM and spin transistors. The paper also outlines potential applications and challenges associated with integrating spintronics into existing semiconductor technologies.

1. Presentation
By
ANNAMACHARIYA INSTITUTE OF TECHNOLOGY & SCIENCES
(Autonomous)
New Boyanapalli,Rajampet

2. •Introduction
•GMR
•Devices
•Advantages and disadvantages
•conclusion

3. Spintronics is a NANO technology which deals with spin
dependent properties of an electron instead of charge dependent
properties

4. •Spin is a quantum mechanical property
•The rotational moment creates a small magnetic field
•The electron spin given a direction up or down
•The up and down direction given a of (1) or (0) same
thing as the electron positive or negative charge
correspond to those values
•Key concept is controlling the spin of electrons

5. What Is Spintronics ?
• In conventional electronics,
electron charge is used for
manipulation, storage, and
transfer of information .
• Spintronics uses electron
spins in addition to or in
place of the electron
charge.

6. Why We Need Spintronics !
Failure of Moore’s Law :
 Moore’s Law states that the number of transistors on a
silicon chip will roughly double every eighteen months.
 But now the transistors & other components have reached
nanoscale dimensions and further reducing
the size would lead to:
1. Scorching heat making making the circuit inoperable.
2. Also Quantum effects come into play at nanoscale
dimensions.
 So the size of transistors & other components cannot be
reduced further.

7. • 1988 France, GMR discovery is
accepted as birth of spintronics
• A Giant MagnetoResistive device is
made of at least two ferromagnetic
layers separated by a spacer layer
• The overall resistance is low for parallel
allignment
• The overall resistance is high for anti
parallel allignment
• Red heads are modern hard drives are
based n the gmr effect

8. Gaint Magnetoresistance (GMR)
 The basic GMR device consists of a layer of non -magnetic metal between two
two magnetic layers.
 A current passes through the layers consisting of spin up or spin down electrons.
 Those oriented in the same direction as the electron spins in a magnetic layer
pass
through quite easily while those oriented in the opposite direction are
scattered.

9. Advantage Spintronics
 Low power consumption.
 Less heat dissipation.
 Spintronic memory is non-volatile.
 Takes up lesser space on chip, thus more compact.
 Spin manipulation is faster , so greater read & write speed.
 Spintronics does not require unique and specialized semiconductors.
Common metals such as Fe, Al, Ag , etc. can be used.

10. 1. MRAM (Magnetoresistive Random access)
2. Spin transistor
3. Quantum Computer

11. •MRAM uses magnetic storage elements instead of electric used in
conventional RAM
•Tunnel junctions are used to read the information stored in
Magnetoresistive Random Access Memory, typically a”0” for zero
point magnetization state and “1” for antiparallel state
•Other advantage of MRAM include smaller size ,lower cost,faster
speed and less power consumption.

12. SRAM VS DRAM VS MRAM
•SRAM
•DRAM
•MRAM
•Fast read and write speed
•Low power
•High density
•Fast speed and write
speed
•Fast read and write speed
•Low power
•High density
•Non volatile
•Volatile
•Low density
•Volatile
•High power
•none

13. •Current passed through a magnetic field becomes spin polarized
•Spin transistors would allow control of the spin current in the same
manner that conventional transistors can switch charge currents
•Using arrays of these spin transistors, MRAM will combine
storage, detection, logic and communication capabilities on a single
chip
•This will remove the distinction between working memory and
storage, combining functionality of many devices into one

14. •The Datta Das Spin Transistor
was first spin device proposed
for metal-oxide geometry,
1989
•Emitter and collector are
ferromagnetic with parallel
magnetizations
•The gate provides magnetic
field
•Current is modulated by the
degree of precession in
electron spin

15. A Quantum
computer, in
contrast, lies on
encoding
information within t
quantum bits or
qubits, each of
which can exist in a
superposition of ‘0’
and ‘1’.

16. PLASTIC MEMORY:
•All the moving electrons inside a sample plastic spin in same
direction-an effect called spin polarisation that could yeild the
plastic memories
•The achieving of spin polarisation happen using magnetic field
•This is first step converting plastic into device
•Plastic spintronic devices would weigh less ,cost less to
manifacture.
•Plastic—vanadium tetra cyanoethanide

17. ELECTRONIC DEVICES
•Based on properties of
charge of the electron
•Classical property
•Meterials:conductors and
semi conductors
•Speed is limited
•Power dissipation is high
SPINTRONIC DEVICES
•Based on intrensic property
spin electron
•Quantum property
•Materials:ferromagnetic
materials
•Speed high
•Power dissipation is low

18. Advantages
•low power consumption
• Multi purpose devices
(amplifiers)
•No electric current required
•Faster Devices
•Larger storage capacity
•Smaller devices
Disadvantages
•Controlling the spin for long
distances
•Combining techniques
between the semiconductor
and magnetic recording
industry
•Difficult to inject and
measure spin in silicon
•Silicon causes electrons to
lose their spin state

19. This technology will exploit the spin of the
electron and create new devices and circuits which
could be more beneficial in future by providing
devices like memories for data base accessing with
the speed of light.
The devices of this technology are very useful
for transaction processing and for scientific number
crunching.

21. By
N balaji Krishna
11701A0412