M91 Fast Hall Controller¶
The Lake Shore M91 Fast Hall controller makes high speed Hall measurements for materials characterization.
More information about the instrument can be found on our website including the manual which has a list of all SCPI commands and queries.
Example Scripts¶
Below are a few example scripts for the M91 Fast Hall Controller that use the Lake Shore Python driver.
Fast Hall Full Sample Analysis¶
from lakeshore import FastHall
from lakeshore import ContactCheckOptimizedParameters, ResistivityLinkParameters, FastHallLinkParameters
# Connect to the first available FastHall over USB
my_fast_hall = FastHall()
# Create an optimized contact check settings object that limits the max current to 1 mA
ccheck_settings = ContactCheckOptimizedParameters(max_current=1e-3)
# Define the DC magnetic field strength of the measurement
magnetic_field_strength = 0.1
# Create a resistivity and FastHall measurement linked settings objects
resistivity_settings = ResistivityLinkParameters()
fasthall_settings = FastHallLinkParameters(magnetic_field_strength)
# Run the optimized contact check to automatically determine the best parameters for the sample
ccheck_results = my_fast_hall.run_complete_contact_check_optimized(ccheck_settings)
# Run a resistivity measurement linking the parameters determined by the contact check
resistivity_results = my_fast_hall.run_complete_resistivity_link(resistivity_settings)
# Prompt the user to insert the sample into the defined field
input("Insert sample into " + str(magnetic_field_strength) + " Tesla field")
# Run the FastHall measurement linking information from the resistivity and contact check measurements
fasthall_results = my_fast_hall.run_complete_fasthall_link(fasthall_settings)
# Dump the data into a text file
results_file = open("sample_analysis.txt", "w")
results_file.write("Contact check results:\n" + str(ccheck_results))
results_file.write("\nResistivity results:\n" + str(resistivity_results))
results_file.write("\nFastHall results:\n" + str(fasthall_results))
Fast Hall Record Contact Check Data¶
from lakeshore import FastHall, ContactCheckManualParameters
# Connect to the first available FastHall over USB
my_fast_hall = FastHall()
# Create a contact check parameters object with desired settings to run a manual Contact Check measurement
ccheck_settings = ContactCheckManualParameters(excitation_type='CURRENT',
excitation_start_value=-10e-6,
excitation_end_value=10e-6,
compliance_limit=1.5,
number_of_points=20)
# Create a file to write data into
file = open("fasthall_data.csv", "w")
# Write header info including the type of test and specific measurements being taken
file.write('Contact Check of Van der Pauw Sample with Varying Current Excitation Ranges\n')
file.write('Contact Pair 1-2\n')
file.write(' , Offset, Slope, R Squared, R Squared Passed, In Compliance, Voltage Overload, Current Overload\n')
# Create a list of current excitation ranges
excitation_ranges = [10e-3, 10e-4, 10e-5, 10e-6]
# Run a separate Contact Check measurement and collect results for each range in the list of excitation ranges
for range_value in excitation_ranges:
# Set the value of the excitation range
ccheck_settings.excitation_range = range_value
# Write the specific excitation range that is being used
file.write('Excitation Range: ' + str(range_value) + 'A\n')
# Run a complete contact check measurement using the settings with the updated excitation range
results = my_fast_hall.run_complete_contact_check_manual(ccheck_settings, sample_type="VDP")
# Collect the measurement results that correlate to the first contact pair (Contact Pair 1-2)
contact_pair_results = results.get('ContactPairIVResults')
pair_one_results = contact_pair_results[0]
# Obtain contact pair result values, then convert them into a list and then a string
logged_keys = ['Offset', 'Slope', 'RSquared', 'RSquaredPass', 'InCompliance', 'VoltageOverload', 'CurrentOverload']
logged_values = [pair_one_results[key] for key in logged_keys]
logged_string = ','.join(str(value) for value in logged_values)
# Write the result values to the file
file.write(',' + logged_string + '\n')
# Close the file so that it can be used by the function
file.close()