Spintronics is an emerging field that uses the spin of electrons rather than their charge to create new devices. Spintronic devices could be smaller, more versatile, and robust than current silicon chips. One example is giant magnetoresistance, where changing the spin orientation of ferromagnetic layers separated by a non-magnetic layer causes large changes in electrical resistance. This effect is used in read heads for hard drives. Another example is magnetoresistive RAM (MRAM), which does not lose stored information when power is turned off. Spintronics offers advantages like lower power consumption and less heat generation than traditional electronics.

1. Spintronics
SAMEER PATEL|AAKASH MASAND

2. Why Spintronics?
 Moore‟s Law:
No. of Transistor doubles
in every 18 months.
 Complexity:
Complex Chip Design &
Power Loss.

3. Introduction To Spintronics
 Conventional electronic devices rely on the transport of electrical charge
carriers – electrons – in a semiconductor such as silicon.
Now, however, physicists are trying to exploit the „spin‟ of the electron
rather than its charge to create a remarkable new generation of
„spintronic‟ devices which will be smaller, more versatile and more robust
than those currently making up silicon chips and circuit elements. The
potential market is worth hundreds of billions of dollars a year.

4. The „Spin‟
 The spin is represented by a
vector. For an electron spinning
“west to east”, the vector points
“north” or “up” and it points
“down” for the opposite spin.
 In an ordinary electronic circuit,
the spins are oriented at random
and have no effect on the current
flow.
 Spintronic devices create spin-
polarized currents and use the spin
to control the current flow.

5. The Giant Magneto Resistance
 A Nano scale phenomena.
 Giant refers to giant change in
resistance due to current.
 It is a quantum mechanical magneto
resistance effect observed in thin-film
structures composed of alternating
ferromagnetic and non-magnetic layers.
The Hard Drive

6. The Structure and Working of GMR
 A Giant Magnetoresistive device is
made of at least two ferromagnetic
layers separated by a spacer layer.
 When the magnetization of the two
outside layers is aligned, the resistance
is at its lowest.
 Conversely when magnetization
vectors are antiparallel, a high
resistance is developed.
 Small fields can produce big effects.
 Parallel and perpendicular currents
are developed depending on the
spin.

7. Magneto Resistive RAM
 An important spintronic
device, which is supposed to be
one of the first spintronic devices
that have been invented, is
MRAM.
 Unlike conventional random-
access, MRAMs do not lose
stored information once the
power is turned off.

8. Quantum Computing
 A quantum computer is a machine that
performs calculations based on the laws of
quantum mechanics, which is the
behavior of particles at the sub-atomic
level.
 A bit of data is represented by a single
atom that is in one of two states denoted
by |0> and |1>. A single bit of this form is
known as a qubit.
 A physical implementation of a qubit
could use the two energy levels of an
atom. An excited state representing |1>
and a ground state representing |0>.

9. Advantages of Spintronics
 Low power consumption.
 Less heat dissipation.
 Takes up lesser space on chip, thus more compact.
 Spin manipulation is faster.
 Spintronics does not require unique and specialized semiconductors.
Common metals such as Fe, Al, etc. can be used.

10. Questions?