MMR's Variable Temperature Hall System (VTHS) allows the user to make automatic measurements of resistivity, mobility and carrier concentration of a wide range of samples using the Van der Pauw method over a temperature range from 70K to 730K. Sample mounting is simple and allows rapid interchange of samples. The VTHS Hall Measurement Controller, the H-50, is compatible with a variety of computers through an IEEE-488 (GPIA) or RS-232 interface. MMR's Benchtop Electromagnet and Programmable Power Supply complement the VTHS. The system uses the VTHS Dewar described below.


  • Operating Temperature: 70 K to 730 K
  • Guarded Triax Leads
  • H-50 interfaces with MMR's Low Temperature Dewar
  • H-50 interfaces with MMR's K-20 Programmable Temperature Controller
  • H-50 interfaces with two different MMR electromagnets, allowing maximum flexibility in sample analysis.
  • Hall magnetometer in Dewar included in system
  • Full software provided for all measurements
  • Power Input: 110 V, 60 Hz and 220 V, 50 Hz
  • H-50 Weight: 12 lb
  • H-50 Dimensions: 3.5" x 17" x 14"

 Variable Temperature Hall Dewar

The VTHS Dewar is a low-profile Dewar designed to fit between the poles of a magnet to enable measurements to be made of the resistivity, Hall mobility and other properties of materials over a wide range of temperatures. Guarded triax leads provide electrical input to the sample via similarly guarded leads on a Kapton Harness to the sample on the cold stage. A Hall sensor immediately adjacent to the sample allows measurement of the magnetic field at the sample location.

In addition to the refrigerator and vacuum chamber, a temperature controller is needed, either manual or programmable; a source of dry nitrogen (99.998% purity); a filter dryer; and a vacuum pump capable of maintaining a vacuum <5 mTorr in the chamber. Other accessories that add to the convenience of operating the system are available from MMR.



  • Operating Temperature: 70 K to 730 K
  • Temperature Stability: ± 0.05 K with K-20 Programmable Controller
  • Temperature Response: 1 K/sec
  • Cooling Capacity: 250 mW at 85 K with nitrogen; 500 mW with Ar at 90 K
  • Cold Pad Size: 14 mm x 10 mm
  • Standard Window Material: Fused silica
  • Optional Window Materials: Sapphire, KRS-5, Ge, etc.
  • Guarded triax leads to sample
  • Four sample leads for Van der Pauw measurements
  • Extra BNC lead for heater for Seebeck measurements
  • Simple sample mounting
  • Integral Hall sensor at sample site
  • Compatible with two different MMR electromagnets, allowing maximum flexibility in sample analysis
  • Dewar Dimensions: 6.0" L x 2.5" W x 0.75" H at sample
  • Weight of Vacuum Chamber: 170 g (6 oz)