Spin Valve Transistor
Spin Valve Transistor
Spin Valve Transistor
CONTENTS
Introduction The spin valve effect Spin valve transistor Spin valve transistor preparation Other spin-valve configurations Advantages & Applications Conclusion
INTRODUCTION
Conventional electronics are based on charge of electron. Spintronics uses spin polarization of electrons. Giant magnetoresistance. Change in resistance when magnetic field is applied. GMR found in magnetic multilayers. Act as valves for electrons with different spin. Electrons with correct spin travel through device.
Emitter bias accelerates electrons over emitter barrier. Probability of passing collector barrier is limited by collisions in base, which affect their energy and trajectory (momentum).
Three important transport processes affect GMR: 1. Spin dependent bulk scattering in magnetic layers. 2. Spin dependent scattering at the interfaces 3. Reflection at the interfaces due to band mismatch between the layers.
Spring 1 is wound up using manipulator 2. Samples 6 is mounted on rotating table 4. Deposition occurs via 5. Substrate selection via magnetically coupled beam3. GMR multilayers and sandwiches are formed.
Granular GMR..
The GMR in granular systems is independent of direction of applied field. The major disadvantage of granular systems is the saturation field which is usually very large.
Advantages
1. Quantum spin valve transistor uses up and down spin states to generate binary data. 2. Currently spin is used for memory,spin valve transistors use it for logic operations. 3. Amplification and switching properties of device is controlled by external magnetic field applied to the device. 4. Spin current releases heat but it is rather less. 5. They do not require power to maintain their memory state.
Applications
High sensitivity magnetic field sensors for data storage applications. It finds its application towards quantum computer.
CONCLUSION
Spin valve transistor is more versatile and robust. Needs to improve magnetic sensitivity of collector current. Spin control is difficult. Pt is to be replaced with metal to minimize cost.
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