A Planar CMOS Field-Emission Vacuum Magnetic Sensor
We have fabricated a CMOS vacuum magnetic sensor that exploits the deflection of an electron beam produced by field emission by a perpendicular magnetic field. The device is planar and fabricated by conventional lithography and etching processes. An extremely high magnetic field sensitivity of 4times103%/T is reported.
High-sensitivity field emission magnetometers and other applications of field emission technologies
The feasibility and development of a field emission based anisotropic vector magnetometer is presented. Within this scope current magnetic sensing technology is investigated and compared. The advantages of, and need for, a field emission based magnetic sensor are then discussed. Background theory, simulation, fabrication, testing; and future developments of field emission magnetometers are presented. The possible applications of field emission to other technologies are also investigated. 
 
The magnetic sensing device presented uses a sharp field emitting tip with a radius of the order of 100nm which is fabricated using standard silicon processing techniques on highly n-doped silicon. Under a vacuum level of , 10^{-6}mBar and at room temperature, a potential applied to a surrounding gate electrode extracts from this tip a beam of electrons which is incident upon two separate anode electrodes. In the absence of an external magnetic field the electron current incident on each of these two electrodes is equal, while in the presence of a magnetic field the Lorenz force skews the beam towards one of the electrodes, resulting in a differential current which is proportional to the magnetic field.
Measurement and Demonstration of Thermal Expansion Coefficient
There are many classroom demonstrations, such as the ball-and-ring experiment, for showing the existence of thermal expansion of solids. The coefficient of linear expansion α (= increase in length divided by the original length times the change in temperature) may be measured in high school laboratories using a number of methods.1–4 In this paper we describe an especially simple experiment for determining α for a metal rod. It is based on the well-known optical lever method and is suitable for either a laboratory experiment or a classroom exercise.