In Spintronics, information is stored and transmitted using another property of electrons called spin. This technology could create new devices and circuits which would be more beneficial in future.

2. CONTENTS

3. What is spintronics??
– Spin Electronics is also called Spintronics
– In electronic devices,information is stored in
0's and 1's.The 0's and 1's of computer
binary code are represented by the
presence or absence of electrons within a
semiconductor or other material.
– In Spintronics, information is stored and
transmitted using another property of
electrons called spin.

4. What is spin..??
• If the electronspins
clockwise on its axis, it is
described as spin-
up;counterclockwise is
spin-down.These two
spins represent 0 and 1 of
binary data.

5. Why spintronics...??
• We use capacitors to store values..if the number of
electrons on capacitor are above threshold value
then it's 1 if not it's 0.
• In the present day chips are containg 100 millions of
transistors..!!
• Further shrinking of chips reaches a
barrier due to leakege
currents,power
consumption,heat...(failure of
moores law)
• Spintronics combined with
nanotechnology gives the best
solution..!!

6. EVOLUTION
• The field of Spintronics was born in the late 1980s with
the discovery of the "Giant Magnetoresistance effect”
by Albert Fert and Peter Grunberg.
• The use of semiconductors for spintronics began with
the theoretical proposal of a spin field-effect-transistor by
Datta and Das in 1990.
• It was pioneered by Meservey and Tedrow by doing
experiments on tunneling.

7. GMR
• The giant magnetoresistance (GMR) effect occurs when
a magnetic field is used to align the spin of electrons in
the material, inducing a large change in the resistance of
a material.
• This change in resistance (also called
magnetoresistance) is used to sense changes in
magnetic fields
• Depending on the relative orientation of the
magnetizations in the magnetic layers, the device
resistance changes from small (parallel magnetizations)
to large (antiparallel magnetizations)

8. SPIN TRANSISTOR
• Here we control the spin orientation by applying a
gate voltage.
• Spin transistor consists of ferromagnetic electrodes
and a semiconductor channel that contains a layer of
electrons and a gate electrode attached to the
semiconductor.

9. SPIN TRANSISTOR
• The spin‐ polarized electrons are injected from the
FM source electrode (FM1).
• If the spin orientation of the electron channel is
aligned to the FM drain electrode, electrons are able
to flow into the FM drain electrode. However, if the
spin orientation is flipped in the electronlayer ,
electrons cannot enter the drain electrode (FM2).
• The rotation can be controlled, in principle, by an
applied electric field through the gate electrode.
• When electron moves through semiconductor in the
presence of electric field it changes its orientation..it
rotates...and therefore cannot enter drain.

10. TMR
• TMR-Tunneling Magneto
Resistive structures
• TMR structures are made
up of insulator
sandwiched between two
ferromagnetic materials.
• Insulator is very resistive
which means electrons
are very unlikely move
through it
• Ferromagnetic is material
in which spins tend to
align in same direction

11. TMR working
• The lower ferromagentic
layer is fixed,its electrons
are forced to have same
spin as adjacent strong
magnet.
• The upper ferromagnetic
layer if free ,its electrons
change their spin
according to surroundings
or through SPIN
TRANSFER TORQUE.

12. • When the spins of
ferromagnetic layers are
parallel they store 1
• When the spins of
ferromagnetic layers are
anti parallel they store 0
Spin transfer torque: Here the electrons change their
spin to match the spins of nearby flowing electrons

13. To READ data
• Computer sends a tiny current through the TMR.
• If the spins are parallel then electron can pass
through TMR structure ,if spins are anti parallel
then electron doesnt pass through TMR structure.
• By seeing how much current reaches the other
side ,computer tells whether the structure is holding
1 or 0

14. To WRITE data
• To write data we send larger currents up or down the
structure.
• sending the current up the layer from fixed layer to free
layer switches the value from 0 to 1.
• Electrons adopt the fixed layer spin as they move
through it, as the free layer adopys to changes spin
changes according to moving electron.

15. INTO MEDICAL FIELD
• The free layer in TMR responds to changes in external
magnetic field...those changes can be caused by
computer or living organism.
• Tiny magnetic fields are created around our body when
there are changes in our functioning...like when virus
attacks....change in heart beat rate ...brain related...
• A spintronic sensor can detect those smallest deviations
from normal magnetic field detecting anything from
bacterial infection to brain tumor..!!!

16. INTO QUANTUM WORLD..!!
• With the conventional high and low states which are
usually represented by simple currents ..the spin of
electron adds to give other bit.
• So 4 possible states evolve here
1.Up - High
2.Up - Low
3.Down - High
4.Down - Low
These four states represents the Qubits.

17. ADVANTAGES..!!
• Less energy is needed to change spin than to generate
a current to maintain electron charges in a device, so
spintronics devices use less power an are fast
• Spin states can be set quickly, which makes transferring
data quicker.
• Electron spin is not energy-dependent, spin is non-
volatile – information sent using spin remains fixed even
after loss of power.
• These are non volatile
• Larger storage
• Smaller devices

18. DISADVANTAGES
• Controlling spin for longer distances
• Combining techniques between semiconductor
and magnetic industry
• Injection and measurement of spin
• Interference with nearest fields.

19. APPLICATIONS
• Spintronic devices are used in the field of mass-
storage devices.
• It is used to compress massive amounts of data
into a small area.
• Spintronics is used in medical field to detect
cancer.
• Magnetic sensors using GMR effect.
• MRAM uses magnetic storage elements instead
of electrically stored.
• Non volatile programmable logic(AND,OR,NOT
gates).

20. Electronics
• Based on properties of
charge on electron
• Classical property
• Conductors and
semiconductors
• Speed is limited and
power dissipation is high
• Based on number of
charges and energy
Spintronics
• Based on intrinsic
property called spin
• Quantum property
• Ferromagnetic materials
• Speed is highand power
dissipation is low
• Two basic spins..spinup
and spin down

21. CONCLUSION
• The GMR is the background to switch from
electronic to spin based devices
• This technology could create new devices and
ciruits which would be more beneficial in future.
• These spintronic devices would lead to quantum
computers and quantum computation based on
electronic solid state devices...

22. References
• http://nanotechnology.unlv.edu/ee453_fall2008_
projects/ee453_project15.pdf
• https://www.youtube.com/watch?v=q3-S5hM-
3QY
• https://phys.org/news/2015-09-shift-electronics-
spintronics-possibilities-faster.html
• https://en.wikipedia.org/wiki/Spintronics#History

23. THANK YOU!!