SQUID Magnetometer:

The main components of the SQUID magnetometer are:

(a) Superconducting magnet (with programmable bipolar power supply);

(b) Superconducting detection coil which is coupled inductively to the sample;

(c) A SQUID connected to the detection coil.

(d) Console panel with necessary electronics to amplify and display the signal.

Figure 30.07: Schematic of (a) a magnetometer and (b) first, (c) second and (d) third order gradiometers.

Importance of Gradiometers:

It is known that any magnetometer or gradiometer made out of a single piece of superconducting wire as shown in Figure 30.07 is sensitive to changes in magnetic flux coupled to the detection coil.

However, as discussed in VCM magnetometer, the translational vibration of the detection coils with respect to a stationary magnetic field causes a noise current to be generated in the detection circuit.