Frequency and temperature dependence of the microwave surface impedance of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films in a dc magnetic field: Investigation of vortex dynamics

Journal Article · Thu Feb 01 04:00:00 EST 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.53.3459· OSTI ID:278729

Belk, N ^[1]; Oates, D E ^[2]; Feld, D A ^[3]; Dresselhaus, G ^[4]; Dresselhaus, M S ^[5]

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1. Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States)
2. Lincoln Laboratory, Massachusetts Institute of Technology, Lexington , Massachusetts 02173-9108 (United States)
3. Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02173-9108 (United States)
4. Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States)
5. Department of Electrical Engineering and Computer Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States)

We report the results of a study of the complex microwave surface impedance {ital Z}{sub {ital S}} resulting from vortex motion in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films in a dc magnetic field applied parallel to the film {ital c} axis. Using the technique of stripline resonators we have measured {ital Z}{sub {ital S}} at frequencies from 1.2 to 22GHz and at temperatures from 5 to 65K in magnetic fields from 0 to 4 T. We find that both the surface resistance {ital R}{sub {ital S}} and the surface reactance {ital X}{sub {ital S}} increase almost linearly with the magnetic field. In zero applied magnetic field we find the frequency dependence of the surface resistance to be {ital f}{sup 2}. In the mixed state, however, there is a significant increase in {ital R}{sub {ital S}}, particularly at lower frequencies, causing {ital R}{sub {ital S}} to be approximately proportional to {ital f}{sup 1.2} at all measured temperatures. We show that fits of these data to models which include only a single pinning energy and a single characteristic pinning frequency are not able to explain our results. We propose that these data indicate the existence of a large number of metastable bound vortex states separated by energy barriers {ital U}{sub {ital b}} whose magnitudes extend from {ital U}{sub {ital b}}{approximately}0 K to several hundred K, and that the dominant part of {ital R}{sub {ital S}} arises from vortex transitions between these states. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 278729
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 6 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARIUM OXIDES
COPPER OXIDES
FREQUENCY DEPENDENCE
GHZ RANGE 01-100
HIGH-TC SUPERCONDUCTORS
IMPEDANCE
MAGNETIC FLUX
MIXED STATE
SUPERCONDUCTING FILMS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
YTTRIUM OXIDES