Very High Precision Measurements of Quantized Hall Resistances

1990 Fiscal Year Final Research Report Summary

• Project/Area Number: 02044128
• Research Category: Grant-in-Aid for international Scientific Research
• Allocation Type: Single-year Grants
• Section: Joint Research
• Research Institution: Gakushuin University
• Principal Investigator: KAWAJI Shinji GAKUSHUIN University, Faculty of Science・ Professor, 理学部, 教授 (00080440)
• Co-Investigator(Kenkyū-buntansha): COOGAN P.C. オーストラリア, CSIRO National Measurement Labor, 主任研究員 ; RICKETTS B.W オーストラリア, CSIRO National Measurement Labor, 主任研究員 ; SMALL G.W. オーストラリア, CSIRO National Measurement Labor, 主幹研究員 ; WAKABAYASHI Junnichi Gakushuin University, Faculty of Science Research Associate, 理学部, 助手 (30129225) ; B. W Ricketts Csiro・ Nml・ Senior Scientist ; P. C Coogann Csiro・ Nml・ Senior Scientist ; G. W Small Csiro・ Nml・ Principal Scientist
• Project Period (FY): 1990
• Keywords: quantized Hall resistance / quantum Hall effect / high precision measurement

Research Abstract

The Head Investigator visited CSIRO・ NML and investigated works carried out by the Impedance Group ; the manufacture of 1 OMEGA standard resistors and the calibration of them based on a calculable capacitor. Two pieces of 1 OMEGA standard resistors were carried by his own hands to Gakushuin University. Dr. Small visited Gakushuin University to collaborate with Kawaji's group in improving automated measurement systems of the very high precision measurements of quantized Hall resistances. Dr. Ricketts visited Gakushuin University with a newly calibrated 1 OMEGA standard resistor to investigate two NML 1 OMEGA standard resistors in Gakushuin. They were found to be kept in a good condition. The new 1 OMEGA standard resistor was carried back to NML to reinvestigate its resistance value. Results of the investigation shall be reported later. Quantized Hall resistances with the quantum number 2 and 4 were measured against reference resistors with the resistance values of 12.9 kohm and 6.45 kohm, respectively, within relative uncertainties smaller than 0.01 ppm for the quantum number 2 and within 0.015 ppm for the quantum number 4, respectively, in a single run of 6 hour measurements using a current of 10 mu A. The reference resistors were calibrated based on the NML 1 OMEGA standard resistors and found that the drifting rate of the reference resistors was 0.0018 ppm per day. The drifting rate of the reference resistors is satisfactorily small for the future work of very high precision measurements of quantized Hall resistances.