How is the magnetoresistance of material measured?
The magnetoresistance, defined as MR(H) = [RAP(Hsat) − RP(H)]/RP(Hsat), of the spin valves and control devices are measured for various Lchan, temperatures (T), and bias conditions (IB) using a standard four-probe alternating-current (AC) lock-in technique.
How do you find magnetoresistance?
In a semiconductor with a single carrier type, the magnetoresistance is proportional to (1 + (μB)2), where μ is the semiconductor mobility (units m2·V−1·s−1 or T −1) and B is the magnetic field (units teslas).
What is magnetoresistance ratio?
Magnetoresistance ratio (MR) as a function of magnetic field (H) for the WS2 spin valve at various temperatures. The spin valve signals are observed at all temperatures in the experiment. However, the magnitude of MR increases by reducing the temperature. (b) The variation in the MR values as a function of temperature.
Why does magnetoresistance increase?
The force on a current-carrying wire in a perpendicular magnetic field is due to the force on the charge carriers moving through the wire. 12. This force on the charge carriers produces an increased resistance as the charge carriers collide more with atoms in the wire. This phenomenon is called magnetoresistance.
What is geometrical magnetoresistance of ψ-MOSFET?
Geometrical magnetoresistance – Ψ-MOSFETs with Corbino configuration ( Fig. 2.1b) have been tested under high magnetic fields, B, perpendicular to the wafer surface. Due to circular symmetry, the Hall effect is suppressed, leading to a ‘geometric’ magnetoresistance (MR): RB/R0 = 1 + μMR2 B 2.
What is the magnetoresistance of a magnet?
This increase in resistance due to the magnetic field is called magnetoresistance. In 2007, Albert Fert and Peter Grünberg were jointly awarded the Nobel Prize for the discovery of giant magnetoresistance. An example of magnetoresistance due to direct action of magnetic field on electric current can be studied on a Corbino disc (see Figure).
What is the magnetoresistance effect of magnetic flux density?
The magnetoresistance effect is small at small magnetic flux densities. The magnetoresistance effect is proportional to the magnetic field change at larger magnetic flux densities, as shown in Figure 31.32.
How can magnetoresistance be used to determine the Fermi surface?
The experimental use of magnetoresistance techniques to determine the Fermi surfaces of various metals has a long and successful history. This is partly due to the relative ease with which resistance measurements can be made, and also because there are many variables which can be adjusted.