More about the M91 FastHall™ measurement controller

See and operate more easily with TiltView™

37° viewing angle

Built for Science. Designed for People.

  • Removes the need for field reversal
  • Applicable to any magnet type
  • More than 100× faster than previous Hall measurements
  • Ideal for measuring low mobility materials

FastHall™ changes the game

FastHall vs CD vs AC Hall comparison



GPIB to LAN converter option

For applications requiring IEEE-488 communications, this converter plugs into the instrument’s LAN port and creates a GPIB-compatible interface. Note that network timing may be affected when using parallel to serial converters. Delays vary with the amount of data transferred and the converter’s activity as messages are received.

Rack mounting kits



Be future-ready with


With free online software updates, your instrument can always have the most current capabilities. And as Lake Shore introduces new options in the future, you can purchase and download them to your instrument. This allows the M91 to grow as your measurement needs evolve.

The MeasureReady M91 FastHall measurement controller offers the ultimate in HMS speed, convenience, and accuracy


The M91 is capable of running a wide array of Hall analysis functions including:

  • Resistivity and Hall voltage via
    • Traditional DC Hall analysis with current and field reversal. Provides error propagated derived parameter calculations.
    • Traditional AC field Hall analysis. Provides error propagated derived parameter calculations.
    • New FastHall™ analysis for van der Pauw samples with no field reversal required. Automatic excitation value and measure range optimization. Provides error propagated derived parameter calculations.
  • Magnetoresistance measurements
  • Anomalous Hall effect
  • Derived parameters calculated and provided by the instrument including carrier type and concentration, Hall mobility, Hall coefficient, and sheet/volume resistivity.


The M91 is extremely fast, reducing analysis time in most cases by 100×. Most commonly measured materials can be analyzed in a few seconds. Even extreme high resistance (up to 200 GΩ) or low mobility (~0.001 cm²/V s) samples can generally be analyzed in under 2 min. Previously, this capability could take hours to complete.

While fast measurements increase throughput, it can also be shown that shorter measurement times reduce the risk of introducing error due to drifting sample parameters occurring from sample heating or ambient temperature changes.

Compatible with most magnet types

The M91 is designed to work with any magnet system including

  • Permanent magnets
  • Electromagnets
  • Superconducting magnets
  • Pulsed magnets (pulse Δt ~100 μs)


Many competitive solutions provide the electrical measurements only leaving the customer to calculate the derived results. The M91 completes all measurement sequences automatically (even optimizing source and measure range settings) and provides all calculated parameters, including the carrier type and concentration, mobility, and the Hall coefficient.

Complete solution

While many “Hall” systems are little more than a source, meter and a generic switch, the M91 combines complete Hall analysis functionality into a single instrument.

The standard M91 integrates:

  • Current source
  • Synchronous voltage measurement
  • Multi-position switching
  • High level automated routines for ohmic contact check, resistivity, Hall voltage, and a full list of derived parameters with a single command
  • General purpose analog and digital I/O for simple system integration

Add a built in teslameter (future option), ideal for automatic field control or monitoring magnetic field (M91-T).

Add in the high-resistance option to enable measurement of samples up to 200 GΩ.


When used in FastHall mode, the field reversal step is eliminated thereby removing potential sources of measurement bias from field alignment errors that would otherwise directly impact results.

M91 rear panel

M91 rear panel


M91 overview

M91 applications