Name : SQUID Magnetometer, Made: 2G Enterprises-SRM 755, USA
Sensitivity : 10 -10 to 10 -11 Am 2
DC SQUIDS: Magnetic dipole moment noise of less than 1x10 -12Am 2 (1x10 -9EMU) RMS per root Hz
DYNAMIC RANGE:1x10 -12 to 2x10 -4Am 2 analog in 4 ranges, 1x10 -12 to 2x10 -3Am 2 digital flux
FIELD ATTENUATION: 10 6 for transverse fields, 10 11 for axial fields
The superconducting quantum interference device (SQUID) consists of two superconductors separated by thin insulating layers to form two parallel Josephson junctions. The device is configured as a magnetometer to detect incredibly small magnetic fields. When the sample is moved up and down it produces an alternating magnetic flux in the pick-up coil .The magnetic signal of the sample is obtained via a Superconducting pick-up coil with 4 windings. This coil is, together with a SQUID antenna, part of a whole superconducting circuit transferring the magnetic flux from the sample to an SQUID device which is located away from the sample in the liquid helium bath. This device acts as a magnetic flux-to-voltage converter. This voltage is then amplified and read out by the magnetometer’s electronics.
Using this kind of equipment we can measure: (a) The real and imaginary components of the AC magnetic susceptibility as a function of frequency, temperature, AC magnetic field amplitude and DC magnetic field value. (b) The DC magnetic moment as a function of temperature, DC magnetic field, and time. Using a specially designed sample holder the magnetic moment as a function of angle can be also measured.