This codebook.txt file was generated on 2019-01-08 by Ilana Michele Percher ------------------- GENERAL INFORMATION ------------------- 1. Title of Dataset: Resistance vs Temperature of an Indium Oxide thin film sample "6.7E-5" at a range of magnetic fields 2. Author Information Principal Investigator Contact Information Name: Allen M. Goldman Institution: University of Minnesota Address: Minneapolis, Minnesota 55455, USA Email: goldman@umn.edu Associate or Co-investigator Contact Information Name: Ilana M. Percher Institution: University of Minnesota Address: Minneapolis, Minnesota 55455, USA Email: percher@umn.edu 3. Date of data collection (single date, range, approximate date): Data for fields 0mT to 1800mT were measured between 2016-08-23 and 2016-09-01 during single cool-down of dilution fridge. (A blockage in the dilution refrigerator required partial warmup of system between 2016-09-11 and 2016-09-23.) Data for fields 2000mT to 12000mT were measured between 2016-09-24 and 2016-10-15. 4. Geographic location of data collection (where was data collected?): Data were measured in the Oxford Kelvinox 25 dilution refrigerator, located in room 20, part of the Goldman lab space in the Physics and Nanotechnology building on University of Minnesota Twin Cities Campus. 5. Information about funding sources that supported the collection of the data: This work was supported by the Condensed Matter Physics Program of the National Science Foundation under grant DMR-12663316. Part of this work was carried out at the University of Minnesota Characterization Facility, a member of the NSF-funded Materials Research Facilities Network via the MRSEC program (DMR-140013), and the Nanofabrication Center which receives partial support from the NSF through the NNIN program. -------------------------- SHARING/ACCESS INFORMATION -------------------------- 1. Licenses/restrictions placed on the data: CC0 1.0 Universal Public Domain Dedication, http://creativecommons.org/publicdomain/zero/1.0/ 2. Links to publications that cite or use the data: Percher, Ilana M., Volotsenko, I., Frydman, A., Shklovskii, B. I. & Goldman, A. M. Vortex variable range hopping in a conventional superconducting film. Phys. Rev. B 96, 224511 (2017) https://doi.org/10.1103/PhysRevB.96.224511 Percher, Ilana. (2018). 2D Mott Hopping of Vortices in an Amorphous Indium Oxide Film. Retrieved from the University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/200277. 3. Links to other publicly accessible locations of the data: 4. Links/relationships to ancillary data sets: 5. Was data derived from another source? No 6. Recommended citation for the data: Percher, Ilana, M; Goldman, Allen, M. (2019). Resistance vs Temperature of an Indium Oxide thin film sample "6.7E-5" at a range of magnetic fields. Retrieved from the Data Repository for the University of Minnesota, https://doi.org/10.13020/cbew-4g28. --------------------- DATA & FILE OVERVIEW --------------------- 1. File List A. Filenames: Data set comprised of 57 files, labeled "RvT__H=mT.txt" where gives the value of the magnetic field applied perpendicular to the sample during measurement. indicates the time of day the data file was created, using either a 12- or 24-hour clock. This was used to differentiate the files resulting from different measurements made at the same field strength. A few files read "combo", indicating that the curve is compiled from two or more parent data files, measured at different times at the same field. Usually this was done to clean up segments of data showing elevated noise levels. These features are thought to result from some electrical disruption extrinsic to the sample. Note: The RvT_1605_H=7000mT.txt file has quality concerns. More information is provided in the Methodology section of this readme. B. Short description: DC sheet resistance of a thin amorphous indium oxide film, measured as a function of temperature at a range of magnetic fields to show a transition from a superconducting state to an insulator-like state. 2. Relationship between files: The data in these files all come from the same sample, in the same measurement configuration, over the course of two fridge cool-downs that were closely spaced in time. The difference between the files is the magnetic field applied to the sample. 3. Additional related data collected that was not included in the current data package: Some AFM data measuring morphology of the sample surface was included in the publications but has not been archived here. 4. Are there multiple versions of the dataset? no -------------------------- File Specific INFORMATION -------------------------- Time (s) = timestamp in seconds Temperature (K) = mixing chamber temperature in degrees Kelvin Field (mT) = magnetic field in millitesla Current (A) = excitation current in Ampere units R_horiz (Ohms) = Horizontal resistance data in Ohms std err R_h (Ohms) = Uncertainty of Horizontal resistance data in Ohms R_vert (Ohms)= Vertical resistance data in Ohms std err R_v (Ohms) = Uncertainty of Vertical resistance data in Ohms Sheet Resistance (Ohms/square) = sheet resistances calculated numerically from the directional components st err R_sheet (Ohms/square) = uncertainty propagated from the directional uncertainties Pulse width (ms) = total duration of DC current pulse in milliseconds Delay (ms) = wait in milliseconds before voltage measurement begins Interval (nPLCs) = wait between current pulse initiation, in integer multiples of the power-line cycle (here, 1/60 s) n pulses = number of current pulses and voltage measurements averaged into final resistance value In each data file, the first four columns provide the timestamp, mixing chamber temperature, magnetic field, and excitation current for each measurement. The fifth through tenth column give measured resistance values, determined using repeated pulses of DC current. Resistance values were the mean of repeated measurements, and were provided with standard error calculated from those measured values. Horizontal and vertical resistance data (and uncertainties) are provided in columns 5-8. Column 9 gives sheet resistances calculated numerically from the directional components, and Column 10 shows the uncertainty propagated from the directional uncertainties. Columns 11-14 give details about the pulse-delta settings used by the Kiethley boxes for each data point. The quantities in columns 11-14 provide specific information about settings used to configure the pulse-delta method provided by the Kiethley current source and voltmeter. "Pulse width" in column 11 refers to the duration of a single current pulse, applied in a square wave. The "Delay" reported in column 12 was set based on the response time of the measurement circuit, so that voltage measurements were made only after the current had risen to the value given in column 4. (The duration of a single voltage measurement would then be column 11 - column 12). Column 14 provides the number of samples made in this fashion used to calculate resistances. Each current pulse was synchronized with the power line signal to eliminate the interference and noise that could result if the signals were out of phase. Thus, wait times between pulses were set as an integer multiple of power line cycles, denoted by "nPLCs", and given in column 13. -------------------------- METHODOLOGICAL INFORMATION -------------------------- 1. Description of methods used for collection/generation of data: These R vs. T curves are "warming curves", in that points were measured in order of ascending temperature. Between each measured data point heat was applied to the sample to raise its temperature, and resistance measurements began only after temperature measurements determined the sample temperature was stable. Resistance thermometry was used to determine the temperature. Resistance values were measured by sourcing a current and measuring the resultant voltage drop across the sample. This was done using a Keithley 6221 precision current source and a Keithley 2182 nanovoltmeter linked together in "pulse-delta" mode. The amorphous indium oxide thin film sample was made in a square pattern, with contacts on the corners. This enabled the measurement of sheet resistance by rotating around this square and averaging in the manner developed by van der Pauw. In this process, resistance is calculated in the orthogonal directions parallel to the film, which we label as "horizontal and "vertical". From these resistances, a sheet resistance was calculated. A more complete description of methods can be found in the thesis: Percher, Ilana. (2018). 2D Mott Hopping of Vortices in an Amorphous Indium Oxide Film. Retrieved from the University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/200277. 2. Methods for processing the data: Sheet resistance was calculated numerically (using an MS Excel macro) from the horizontal and vertical components of resistance using the van der Pauw method. Uncertainty for these values was estimated to be the geometric mean of the uncertainties for the directional components of the resistance. 3. Instrument- or software-specific information needed to interpret the data: 4. Standards and calibration information, if appropriate: Temperature measurements were made using a Ruthenium Oxide thermometer last calibrated by LakeShore >10 years ago. 5. Environmental/experimental conditions: 6. Describe any quality-assurance procedures performed on the data: I-V data were collected at base temperature before each R vs. T curve to verify that the resistances measured fell within the linear Ohmic regime. Resistance vs. Temperature data measured using the pulse-delta technique were found to be comparable to data measured using much longer DC pulses at several low fields. At higher fields and lower temperatures, where the sample was more resistive, differences between the curves indicated that power delivered to the sample during measurement contributed to its heating. As a lower-power measurement technique, the pulse-delta measurements were considered more accurate. NOTE: The magnetic field strengths were determined via calibration between the superconducting magnet power supply's sourced current and the specifications of the magnet itself. This is thought to be a reliable measure as results were consistent with each other as well prior measurements using a different magnet. The one exception is the curve measured at 7T, which does not interpolate with its neighbors. These data are included here for completeness, but this lack of consistency signals that the field was likely below 7T during these measurements. The magnet power supply sometimes suffered errors and reset itself during use. It is possible that this occurred in the middle of ramping the magnet from 6T to 7T, and the measurement sequence to this as a signal that the sample had reached the desired field. This would explain the discrepancy between these and the rest of the data. 7. People involved with sample collection, processing, analysis and/or submission: Ilana M. Percher Danqing Deng