High precision metrology based microwave effective linewidth measurement technique

Journal Article · Thu Nov 15 00:00:00 EST 2007 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2813344· OSTI ID:21024592

Mo, Nan; Green, Jerome J; Beitscher, Bailey A; Patton, Carl E ^[1]

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1. Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

A precision microwave effective linewidth measurement technique for magnetic samples has been developed. The measurement utilizes a high-Q cylindrical cavity that contains the sample of interest, a highly stable and programable static magnetic field source, a computer controlled network analyzer for cavity center frequency {omega}{sub c} and quality factor Q{sub c} determinations, and the standard metrological substitution ABA method for accurate relative {omega}{sub c} and Q{sub c} measurements. Sequential long term ABA measurements show that the time and temperature drifts and random errors are the dominant sources of error, with uncertainties in {omega}{sub c}/2{pi} and Q{sub c} in the range of 50 kHz and 25, respectively. The ABA method is applied to eliminate these drifts and minimize the random errors. For measurements over 25 ABA cycles, accuracy is improved to 0.14 kHz for {omega}{sub c}/2{pi} and 3 for Q{sub c}. The temperature variation over a single ABA cycle is generally on the order of 10{sup -3}-10{sup -5} deg. C and there is no need for any further temperature stabilization or correction measures. The overall uncertainty in the 10 GHz effective linewidth determinations for a 3 mm diam, 0.5 mm thick polycrystalline yttrium iron garnet (YIG) disk is 0.15 Oe or less, well below the intrinsic single crystal YIG linewidth. This represents a factor of 10 improvement in measurement accuracy over previous work.

• OSTI ID: 21024592
• Journal Information: Review of Scientific Instruments, Vol. 78, Issue 11; Other Information: DOI: 10.1063/1.2813344; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ACCURACY
CAVITY RESONATORS
CYLINDRICAL CONFIGURATION
ERRORS
FERRITE GARNETS
FREQUENCY MEASUREMENT
GARNETS
GHZ RANGE
IRON OXIDES
KHZ RANGE 01-100
MAGNETIC FIELDS
MICROWAVE RADIATION
MONOCRYSTALS
POLYCRYSTALS
QUALITY FACTOR
YTTRIUM
YTTRIUM COMPOUNDS