Relationship between the surface resistance and crystal orientation of YBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin film

Ohshima, Shigetoshi; Kusünoki, Masanobu; Mukaida, Masashi; Suzuki, Toshiharu; Chibai, K.; Inadomaru, M.; Takano, Y.

doi:10.1109/77.919816

Cited by 12 publications

(11 citation statements)

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“…While the microwave surface resistance (R S ) of YBa 2 Cu 3 O 7−δ (YBCO) films already appears low enough to meet the minimum requirements for microwave transceivers [1], lower R S can still have a dramatic effect on device performance. Therefore, studies to reduce the R S , to improve its power dependence, as well as to clarify the factors that influence the R S of YBCO are still in progress [2][3][4][5][6][7]. There have been reports that disorder [2], defects [3] and outgrowths [4] in the YBCO films are some of the factors that affect the R S .…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…There are also many reports that describe relations between the R S of YBCO films and their crystal structures [5][6][7]. Char et al [5] and Ohshima et al [6] have reported that in-plane orientations of YBCO films could affect their R S values significantly. Meanwhile, there is a report by Zaitsev et al, which argues that the highest possible degree of the lattice alignment is not essential for realizing low R S [7].…”

Section: Introductionmentioning

confidence: 99%

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Correlation between the microwave surface resistance and the crystal structures of YBa₂Cu₃O₇films on CeO₂-buffered sapphire

Lee

Lee³

2003

Supercond. Sci. Technol.

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Dependence of the microwave surface resistance (R S ) of YBa 2 Cu 3 O 7−δ (YBCO) films on their crystal structures was studied for YBCO films grown on as-prepared CeO 2 -buffered sapphire (CbS) and CbS post-annealed at 950-1100 • C. At temperatures below 70 K, the R S appeared to be strongly dependent on the degree of the in-plane alignment of the YBCO films as determined by x-ray φ-scan analysis. Optimum in-plane alignment could be observed for YBCO films on CbS post-annealed at 1000-1050 • C, with the R S appearing significantly smaller than for YBCO films prepared on as-grown CbS or CbS post-annealed at the other temperatures. Conversely, we observed a small correlation between the R S and the degree of the c-axis alignment as determined using x-ray ω-scan analysis. Similarly, surface roughness of the YBCO films did not strongly influence R S at temperatures below 70 K.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Correlation between the microwave surface resistance and the crystal structures of YBa₂Cu₃O₇films on CeO₂-buffered sapphire

Lee

Lee³

2003

Supercond. Sci. Technol.

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“…The microwave losses and the power dependence of the surface impedance are expected to be small in LPE films optimized for microwave properties because of small number of grains and grain boundaries [1,7]. A contamination of grain boundaries [6] and a presence of misoriented grains [12] can cause an increase of microwave losses in the sample.…”

Section: Introductionmentioning

confidence: 99%

Investigation of microwave losses in superconducting liquid phase epitaxy Y_0.7Yb_0.3Ba₂Cu₃O₇films

Nurgaliev

Purnell

et al. 2003

Supercond. Sci. Technol.

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Liquid phase epitaxy (LPE) is a prospective method for preparing high quality superconducting thick films, suitable for microwave application. In this paper, the microwave parameters of two selected LPE Y 0.7 Yb 0.3 Ba 2 Cu 3 O 7−δ thick (∼3 µm) films on single crystal MgO substrates with 77 K critical current densities 0.6 MA cm −2 and 0.08 MA m −2 were investigated between 20 and 90 K and at 2.7 GHz and 9.2 GHz. The dependence of the impedance on the microwave power level was ascribed to the effect of the weak links in the samples, and some parameters of weak links were evaluated. Cleaning the surface with 0.1 vol% Br 2 in methanol reduced the microwave losses for short etching times.

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“…1 shows R eff (T) of a 400nm-thick YBCO film on a 340nm-thick CeO 2 /YSZ/CeO 2 trilayer on textured Ni [41]. While the low normal-state resistance is related to the low impedance of the thin buffer and the metallic substrate, the high R s -level in the superconducting state is attributed to low-and large-angle grain boundaries or microcracks [5,[42][43][44]. These effects add not only to the total surface resistance but lead also to a larger thickness correction due to an enhanced penetration length.…”

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Recent developments in the characterization of superconducting films by microwaves

Hein

Getta

Kreiskott

et al. 2002

Physica C: Superconductivity

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We describe and analyze selected surface impedance data recently obtained by different groups on cuprate, ruthenate and diboride superconducting films on metallic and dielectric substrates for fundamental studies and microwave applications. The discussion includes a first review of microwave data on MgB 2 , the weak-link behaviour of RABiTS-type YBa 2 Cu 3 O 7-δ tapes, and the observation of a strong anomalous powerdependence of the microwave losses in MgO at low temperatures. We demonstrate how microwave measurements can be used to investigate electronic, magnetic, and dielectric dissipation and relaxation in the films and substrates. The impact of such studies reaches from the extraction of microscopic information to the engineering of materials and further on to applications in power systems and communication technology.Keywords: Surface impedance, superconducting films, microwave dissipation, relaxation.Address: Dr. Matthias Hein, Dept. of Physics, Univ. of Wuppertal, D-42097 Wuppertal, Germany. Tel. +49(202) 439-2747, Fax +49(202) Email: mhein@venus.physik.uni-wuppertal.de M. Hein et al., EUCAS 2001, invited paper B3-01, page 2 of 19 Microwave measurements in condensed matter physics Theoretical backgroundThis paper illustrates the relevance of microwave measurements for the investigation of electronic and magnetic transport and ordering in condensed matter. While most work has been done on solids, the described techniques could also be adapted to soft matter or liquids.The presentation is based on a selection of examples and does not attempt to provide a complete description of activities in this field.The complex-valued surface impedance Z s =R s +iX s at a microwave frequency ω=2πf is related to the permeability and conductivity of a material, µ and σ, in the local limit by ) (where R s and X s are the surface resistance and reactance [1]. The material parameters µ and σ are complex-valued and frequency dependent, e.g., via electronic, magnetic, or dielectric relaxation. The generalized conductivity σ characterizes electrical conduction through transport and displacement currents.The electrodynamic response of metallic materials provides information on the electronic properties within a surface layer of the order of the London penetration depth ~200 nm, and on a variable time scale ∼1/ω. Such information is complementary to thermodynamic bulk properties and low-frequency transport data. The high frequencies also help to derive Fermi surface properties, which would require strong magnetic fields at very low temperatures otherwise [2]. We will focus in the following on superconductors, for which Z s bears information on the density of states and quasiparticle excitations above and below the transition temperature T c [3]. It is also related to the phase purity, grain connectivity and interface effects of technical materials, which cannot readily be studied at similar resolution by At present at least 50 renowned academic and industrial groups study superconductors at microwave frequencies, to ...

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Relationship between the surface resistance and crystal orientation of YBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin film

Cited by 12 publications

References 7 publications

Correlation between the microwave surface resistance and the crystal structures of YBa₂Cu₃O₇films on CeO₂-buffered sapphire

Correlation between the microwave surface resistance and the crystal structures of YBa₂Cu₃O₇films on CeO₂-buffered sapphire

Investigation of microwave losses in superconducting liquid phase epitaxy Y_0.7Yb_0.3Ba₂Cu₃O₇films

Recent developments in the characterization of superconducting films by microwaves

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Relationship between the surface resistance and crystal orientation of YBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin film

Cited by 12 publications

References 7 publications

Correlation between the microwave surface resistance and the crystal structures of YBa2Cu3O7 films on CeO2-buffered sapphire

Correlation between the microwave surface resistance and the crystal structures of YBa2Cu3O7 films on CeO2-buffered sapphire

Investigation of microwave losses in superconducting liquid phase epitaxy Y0.7Yb0.3Ba2Cu3O7 films

Recent developments in the characterization of superconducting films by microwaves

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Correlation between the microwave surface resistance and the crystal structures of YBa₂Cu₃O₇films on CeO₂-buffered sapphire

Correlation between the microwave surface resistance and the crystal structures of YBa₂Cu₃O₇films on CeO₂-buffered sapphire

Investigation of microwave losses in superconducting liquid phase epitaxy Y_0.7Yb_0.3Ba₂Cu₃O₇films