a branch of nano electronics that will improve technology by adding new freedom degrees to electronic for transfer and store information better than electronic devices :)
1. In The Name of Allah
Peresentation by : Javad Zallaghi & Amir Rezaei
SPINTRONICS
2. Introduction
In chemistry We read that electrons and other elementary particles Apart from
the electric charge and mass,have another property called spin, which is a intrinsic
property of electrons
Spin is a Quantum property :)
Types of Properties
3. Spin(Physics)
Definetion : in Quantume Mechanics, spin is an intrinsic form of angular momentum carried
by elementary particles, composite particles,and Atomic nuclie
Word mean of Spin : Rotation
4. conventional definition of the spin
quantum number
S =
𝑛
2
, n can be any non-negative integer number
For any Physical System S is quantized
𝑆 =
ℎ
4𝜋
𝑛(𝑛 + 2)
Description: Hence the allowed values of s are 0, 1/2, 1, 3/2, 2, etc
S is The spin angular momentum
h is the Planck constant
5. Spintronic or Electero Spin
Definetion1 : Electrones in atom, In addition to influence of gravity,revolves
around it, Have a rotary motion around their own that we call it Spin of Electeron.
Science of this motion analysis is Spintronic :)
Definetion2 : Spintronics is a new branch of electronics in which electron spin, in
addition to charge, is manipulated to yield a desired electronic outcome. The spin
itself is manifested as a detectable weak magnetic energy state characterized as
“spin up” or “spin down”
Theory : Spintronics electronics,is the study of electron spin in materials in order
to better understand its behavior,with the hope of developing an entirely new
generation of microelectronic devices
6. History
Spintronics burst on the scene in 1988 when French and German physicists
discovered a very powerful effect called Giant Magnetoresistance (GMR)
What is GMR ? Giant Magnetoresistance is a effect observed in thin-film
structures composed of alternating ferromagnetic and non-magnetic conductive
layers
In 1988 Fert discovered the Giant magnetoresistance effect (GMR) in multilayers
of iron and chromium.He was awarded the 2007 Nobel Prize at Physics
Gigabyte Hard Disk
7. Explaining
An electron is just like a spinning sphere of charge
Spin make electrone behave almost as if it were a magnet twirling about the axis
connecting its north and south poles.Electron can have spins oriented in different
directions
A magnetic field causes an electron to swivel like a needle of a compass
When the magnetic field is removed,the electron stops processing and locks the
orientation of its spin
8. Why Spintronic ?
The spin of the electron has three states to it; up, down, and in between
In today’s world of computers the spin is ignored and you have either on/off, 0/1, or up/down but
with the spin of the electron you can have many states and not be limited with those two states
Answer : Because of these many states information can be processed a whole lot faster if an
electrons spin carries data
Moore’s Law : No. of Transistor doubles in every 18 months
Complexity : Complex Chip Design & Power Loss
Motivation : Spintronics-Information is carried not by electron charge but by it’s spin
9. Spintronic Devices & Moore’s Law
Conventional electronic devices ignore the
spin property and rely strictly on the transport of
the electrical charge of electrons
• Adding the spin degree of freedom provides
new effects, new capabilities
• As electronic devices become smaller :)
• Spintronic devices offer the possibility of
– higher speed, and
– reduced power consumption
10. The Spin Advantage
Information is stored into spin as one of two possible orientations
Spin lifetime is relatively long, on the order of nanoseconds
Spin currents can be manipulated
Magnetic storage is nonvolatile
Binary spin polarization offers the possibility of applications as qubits in quantum
computers
12. Giant Magnetoresistance(GMR)
What is MG ? Magnetoresistance is the tendency of a material to change the
value of its electrical resistance in an externally-applied magnetic field
dependence of electrical resistance on magnetic field (ΔR/R)B
13. The GMR Effect
Parallel Anti-parallel
• Change of electron mobility observed
between spin up and spin down
electrons in traversing a ferromagnet
• If spin of the electron is parallel to the
spins in the ferromagnet, the
scattering(resistivity) is less than if the
spin traverses a ferromagnetic region of
antiparallel spins
• Regions with small dimensions so that
electron spin directon is preserved
during the traversal
14. GMR-The Origin
The Nobel Prize in Physics 2007
"for the discovery of Giant Magnetoresistance“
GMR was discovered in 1988 in Fe/Cr/Fe trilayers by a
research team led by Peter Grünberg of the Jülich Research
Centre(DE), who owns the patent. It was also simultaneously
but independently discovered in Fe/Cr multilayers by the
group of Albert Fert of the University of Paris-Sud (FR)
Albet Fert Peter Grunberg
15. Tunnel Magnetojunction
TMR : Tunnel Magnetoresistance
Like GMR but better
Multilayer junction filter
Quantum mechanical principle
2 layers of magnetic metal, separated by an
ultrathin layer of insulator, about one nm
Tunneling effect
16. History Of TMJ(TMR Effect)
1975 : Muliere | Fe/Ge-O/Co | TMR= -14 %
1994 : Miyazaki | ? | TMR= -18%
2004 : Parkin and Yuasa | Fe/MgO/Fe | TMR= -200%
2008 : S. Ikeda, H. Ohno | CoFeB/MgO/CoFeB | TMR= -1100%
