YBa2Cu3O7-δ Films Research Articles

Thick <formula formulatype="inline"><tex Notation="TeX">$\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7-\delta}$ </tex></formula> Superconducting Films by Low-Fluorine Metallorganic Solution Deposition

YBa 2 Cu 3 O 7-δ (YBCO) coated conductor has been a promising candidate for high-current transportation material in industry, while the critical current (I c ) becomes a limitation for large-scale application. An efficient way to improve I c is to increase the thickness of YBCO film without much reduction in critical current density (J c ). Metallorganic solution deposition (MOD) is a traditional method to fabricate YBCO films while it takes time as long as 10h during the pyrolysis process. In comparison, Low-Fluorine MOD (LF-MOD) method is applied to reduce the pyrolysis time to less than 2h. In this paper, we successfully obtain YBCO thick films up to 1.7μm by double dip coating process using low-fluorine MOD method. Though wrinkles are frequently observed on the surface of the first layer after pyrolysis at 400 °C for 0.5h, the surface of the final double coated YBCO thick film is homogeneous and cracks are hardly found. Further tests show relatively good c-axis orientation and J c value of about 10 5 A/cm 2 at 77K. With an optimization for the pyrolysis and crystallization processes, better superconducting properties of YBCO thick film are expected.

Polymer assisted thick single-layer YBa2Cu3O7-δ films prepared with modified TFA-MOD method

Single-layer YBa2Cu3O7-δ (YBCO) films with the thickness of over 600 nm were fabricated by modified metal organic deposition using trifluoroacetate metal organic deposition (TFA-MOD) method on LaAlO3 (LAO) substrates. Polyvinylbutyral (PVB) was added into the precursor solution to enhance the thickness of the single layer. The pyrolysis process was shortened to about 3 h due to the reduction of the fluorine content in the precursor solution. The effects of heating rate during the crystallization process on the microstructure and J c values of YBCO films were investigated. The a-axis-oriented YBCO crystals dominate when the heating rate is lower than 20 °C·min−1, while faster heating rate of 43 °C·min−1 results in pure c-axis epitaxial growth. The J c values of YBCO films increase linearly with heating rate increasing due to the increase of c-axis YBCO growth, and the critical current (I c) value of 100 A·cm−1 within a single-layer YBCO film is achieved.

An effective approach to achieving low supersaturation for a/b-axis oriented YBa2Cu3O7−δfilm growth

Using liquid phase epitaxy, a novel approach was developed to grow a-axis oriented YBa2Cu3O7-δ films (a-films) under an air atmosphere, which has been difficult previously since its formation requires extremely low supersaturation. In our new method, instead of conventional cooling from the saturated to supersaturated state, an extremely small driving force for film growth was generated from the unsaturated through saturated to supersaturated state. By controlling the amount of fresh solvent and the melting time before cooling down the Y-Ba-Cu-O solution, a growth region width up to 30 K was acquired for preparing a-films. Significantly, this work provides a low-cost and convenient way to produce high-quality a-films, which are potentially suitable for Josephson junction devices.

Double-sided reel-to-reel metal-organic chemical vapor deposition system of YBa2Cu3O7-δ thin films

Two-micrometer thick YBa2Cu3O7-δ (YBCO) films have been successfully deposited on both sides of LaAlO3 single crystalline substrates by using a home-made reel-to-reel metal-organic chemical vapor deposition (MOCVD) system, which has two opposite symmetrical shower heads and a special-designed heater. This technique can simultaneously fabricate double-sided films with high deposition rate up to 500 nm/min, and lead to doubling current carrying capability of YBCO, especially for coated conductors (CCs). X-ray diffraction analysis showed that YBCO films were well crystallized and highly epitaxial with the full width at half maximum values of 0.2° ∼ 0.3° for the rocking curves of (005) YBCO and 1.0° for Φ-scans of (103) YBCO. Scanning electron microscope revealed dense, crack-free, slightly rough surface with Ba-Cu-O precipitates. The films showed critical current density (Jc, 77 K, 0 T) of about 1 MA/cm2, and overall critical current of 400 A/cm, ascribed to the double-sided structure. Our results also demonstrated that the temperature and composition in the deposition zone were uniform, which made MOCVD preparation of low cost and high performance double-sided YBCO CCs more promising for industrialization.

Pulsed laser deposition of thick BaHfO3-doped YBa2Cu307-δ films on highly alloyed textured Ni-W tapes

YBa2Cu3O7-δ (YBCO) films with a thickness of up to 3 μm containing nano-sized BaHfO3 (BHO) have been grown on Y2O3/Y-stabilized ZrO2/CeO2 buffered Ni-9at% W tapes by pulsed laser deposition (PLD). Structural characterization by means of X-ray diffraction confirmed that the YBCO layer grew epitaxial. A superconducting transition temperature Tc of about 89 K with a transition width of 1 K was determined, decreasing with increasing BHO content. Critical current density in self-field and at 0.3 T increased with increasing dopant level.

Rapid thermal decomposition for YBa2Cu3O7−δ films derived by DEA-modified TFA-MOD

Thermal decomposition of YBa2Cu3O7-δ (YBCO) films derived by diethanolamine (DEA)-modified trifluoroacetic acid-metal organic deposition (TFA-MOD) was investigated with respect to the understanding of the correlation between the stress releasing and rapid decomposition. It is revealed that the evaporation of DEA and the decomposition of precursor films occur simultaneously. A pyrolysis time as 20 seconds is optimal to keep the proper amount of DEA which prevents the films from severe stress during the pyrolysis. Then smooth surface of resultant films appears. In case of a pyrolysis time longer than 40 s, cracks emerge in the films accompanied with complete evaporation of DEA and appearance of Cu-rich particles, while films with pyrolysis time shorter than 10s is excessively soft, with large amount of DEA and TFA remaining in the film, implying insufficient pyrolysis.

Microwave losses of undoped n-type silicon and undoped 4H-SiC single crystals at cryogenic temperatures

We investigated microwave losses of single-crystalline Si and 4H-SiC at cryogenic temperatures at 8.6–24 GHz using a method involving a dielectric resonator with high-Tc superconductor YBa2Cu3O7-δ films used to improve the measurement sensitivity. The loss tangent of our undoped n-type Si appeared to be extremely low at temperatures below 20 K with a value of 1 × 10−6 at 24 GHz at 10 K, which is more than 100 times lower than the value of 2 × 10−4 at 6.8 GHz at 10 K reported by Krupka et al. [IEEE Trans. Microw. Theory Tech. 54, 3995 (2006)] for undoped p-type Si. Meanwhile, the loss tangent of pristine 4H-SiC appeared to be very high with a value of 0.01 at 10 K at 8.6 GHz, which is 4000 times higher than that of our undoped Si. When the pristine 4H-SiC was irradiated with thermal neutrons, the loss tangent was enhanced by seven times due to the significantly reduced electrical resistivity. Our results show that, at temperatures below 20 K, the loss tangent of undoped n-type Si is low enough for various cryogenic applications and that thermal neutron irradiation could provide a useful means of reducing the electrical resistivity of SiC possibly by means of neutron transmutation doping.

Strong vortex matching effects in YBCO films with periodic modulations of the superconducting order parameter fabricated by masked ion irradiation

We report on measurements of the magnetoresistance and of the critical current in thin films of the high-temperature superconductor YBa2Cu3O7-δ (YBCO). A square array of regions with suppressed superconducting order parameter has been created in these films by introducing point defects via irradiation with He+ ions through a silicon stencil mask. In such a structure distinct peaks of the critical current can be observed at commensurate arrangements of magnetic flux quanta with the artificial defect lattice. Concurrently, the magnetoresistance shows pronounced minima. Both observations demonstrate that the strong intrinsic pinning in YBCO can be overcome by a periodic array of ion-damage columns with 300nm spacing.

Fe-doped epitaxial YBCO films prepared by chemical solution deposition

YBa2Cu3O7-δ (YBCO)-coated conductors have wide-ranging potential in large-scale applications such as superconducting maglev trains and superconducting electric cables, but low current carrying capability restrains the practical application of YBCO-coated conductors at high temperatures and high magnetic fields. It is crucial to develop YBCO-coated conductors with high critical current density. In this paper, epitaxial, dense, smooth, and crack-free Fe-doped YBCO films were prepared on a LaAlO3 single crystal substrate via a fluorine-free polymer-assisted metal organic deposition method. The effects of the dilute Fe doping on microstructure and superconducting character of YBCO films were investigated. The critical temperature for superconducting of the Fe-doped YBCO films decreases slightly. However, the in-field critical current density of YBCO films improves with dilute Fe doping of amounts less than x = 0.005, compared to the pure YBCO film. Therefore, the current carrying capability of YBCO film can improve by doping with appropriate amounts of Fe. This means that dilute Fe doping in YBCO films may be a feasible way to prepare high-performance coated conductors.

Preparation of YBa2Cu3O7-δ superconducting thick film on Ni-W tapes via electrophoretic deposition

The preparation of La0.4Sr0.6TiO3 (LSTO) buffer layer and YBa2Cu3O7-δ (YBCO) superconducting thick film by a low cost technology was studied. The crystal orientation of LSTO and YBCO films was detected by X-ray diffraction, the conductivity of LSTO film and superconductivity of YBCO coating were investigated by standard four-probe method. Excellent in-plane alignment, smooth and dense LSTO buffer layer was successfully prepared on textured Ni-W taps by metal organic deposition (MOD). YBCO thick film was fabricated by electrophoretic deposition (EPD). The effects of applied voltage and deposition time on the YBCO coatings properties were studied. The results show that the critical current density of the YBCO coating deposited under 138 V for 35 min was about 600 A/cm2 (0 T, 77 K).

Influence of Thickness on Performances of YBa$lt;inf$gt;2$lt;/inf$gt;Cu$lt;inf$gt;3$lt;/inf$gt;O$lt;inf$gt;7-δ$lt;/inf$gt; Films Prepared by Metal Organic Solution Deposition

Trifluoroacetate metal organic deposition (TFA-MOD) is one of the most promising technology routes for fabrication of YBa2Cu3O7-δ (YBCO) coated conductors. In this paper, high-boiling point organic solvent diethanolamine (DEA) was added to modulate and to improve the properties of precursor solution by suppression the defect in the final films. And the thickness of single coated film was increased by increased concentration of the metal ions in the precursor solution. It is revealed that an exponential relationship was found between the thickness of precursor film after low-temperature decomposition and the ion concentration, as well as the viscosity of precursor solution vs the ion concentration. Optimizing the ion concentration and dip-coating parameters, smooth and crack-free YBCO films after crystallization are achieved with the thickness more than 1.3 μm. The films show homogeneous microstructures while dispersive heterogeneous particles appear in the surface of the thick films. Critical current density (Jc) measurement shows a decrease of Jc due to the increase of the thickness of YBCO films prepared by high concentration precursor solution, while critical currents (Ic) are distinctly improved. For instance, the Ic value of YBCO film prepared by 2.5 mol/L precursor solution is 4.7 times of that by 1.0 mol/L precursor solution. 1168 无 机 材 料 学 报 第 29 卷

Fabrication of YBCO/CeO2/YBCO multilayer films through an all chemical solution deposition approach

In this paper, the growth characteristics and superconducting properties of YBCO/CeO2/YBCO multilayer films derived from an all chemical solution deposition process layer by layer are investigated. X-ray diffraction results show that the c-axis epitaxial growth feature of the bottom YBa2Cu3O7-δ (YBCO) film was perfectly inherited. Alternating epitaxial growth of YBCO/CeO2/YBCO multilayer films was confirmed by high resolution transmission electron microscopy in combination with selected area electron diffraction, which will lay the groundwork for preparation of SIS-type Josephson junctions. In addition, nanosized BaCeO3 particle rather than BaCeO3 transition layer was observed in the interface between YBCO and CeO2. The superconductivity measurement results show that the proposal method gives better superconducting properties only for high magnetic field and at low magnetic field it deteriorates the superconducting properties.

High-Jc YBa2Cu3O7−δ superconducting film grown by laser-assisted chemical vapor deposition using a single liquid source and its microstructure

A YBa2Cu3O7-δ (YBCO) film was prepared on a multilayer-coated Hastelloy C276 substrate by laser-assisted metalorganic chemical vapor deposition using a single liquid source precursor. A c-axis-oriented YBCO film was grown epitaxially on a (100) CeO2 layer at a deposition rate of 11 μm h−1. A screw dislocation and stacking faults were observed in the cross-section of the YBCO film. The critical current density of the YBCO film reached 2.7 MA cm−2.

Engineering nanocolumnar defect configurations for optimized vortex pinning in high temperature superconducting nanocomposite wires

We report microstructural design via control of BaZrO3 (BZO) defect density in high temperature superconducting (HTS) wires based on epitaxial YBa2Cu3O7-δ (YBCO) films to achieve the highest critical current density, Jc, at different fields, H. We find the occurrence of Jc(H) cross-over between the films with 1–4 vol% BZO, indicating that optimal BZO doping is strongly field-dependent. The matching fields, Bφ, estimated by the number density of BZO nanocolumns are matched to the field ranges for which 1–4 vol% BZO-doped films exhibit the highest Jc(H). With incorporation of BZO defects with the controlled density, we fabricate 4-μm-thick single layer, YBCO + BZO nanocomposite film having the critical current (Ic) of ~1000 A cm−1 at 77 K, self-field and the record minimum Ic, Ic(min), of 455 A cm−1 at 65 K and 3 T for all field angles. This Ic(min) is the largest value ever reported from HTS films fabricated on metallic templates.

Effect of $\hbox{Y}_{2}\hbox{O}_{3}$ Seed Layer on Epitaxial Growth of Oxide Barrier Layer for YBCO Coated Conductor

Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film was deposited as the seed layer by dc reactive sputtering technique on a Ni-5at%W (NiW) substrate. The subsequent oxide buffer layers were introduced as well such as Gd <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> (GZO) and La <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> (LZO). The effects of Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> seed layer on the epitaxial growth of buffer layers and the performance of YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-δ</sub> (YBCO) films were investigated. The atomic force microscopy images showed that the surfaces of Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> seed layers were homogeneous and flat with the root mean square roughness of about 1.2 nm, which is significant for the subsequent layers. In contrast, root mean square roughness values of GZO films on bare NiW or Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> seeded NiW were normally about 2.7-3.4 nm. A series of X-ray studies indicated that the GZO and LZO oxide barrier layers on Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> can be epitaxially grown easily with a wide processing condition of water vapor partial pressure. Furthermore, the effect of Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> seed layer on subsequent YBCO films was investigated by comparing the transition temperature Tc and the critical current density .Ic between YBCO/GZO/NiW and YBCO/GZO/Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /NiW. These results demonstrate the notable role of the Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> seed layer, not only on high-efficiency production of subsequent functional, but also on the improvement of superconducting performances of YBCO films.

Enhanced Flux Pinning Properties of MOD-Processed $ \hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7 - \delta}$ Thin Films With $\hbox{BaZrO}_{3}$ Nanoparticles Using a Ba-Deficient Coating Solution

We report the flux pinning properties of YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-δ</sub> (YBCO) thin films with BaZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (BZO) nanoparticles, fabricated by a fluorine-reduced trifluoroacetate-metal-organic deposition process. For this study, the Ba-deficient coating solutions (Y : Ba : Cu = 1 : 1.5 : 3) with various BZO contents ranging from 0 to 15 mol% were prepared by mixing Ba-trifluoroacetate with fluorine-free Y, Cu, and Zr sources. Precursor films were deposited on SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (001) substrates by dip-coating, pyrolized in a humid oxygen atmosphere, and finally fired at a high temperature in a reduced oxygen atmosphere. Highly enhanced critical current densities (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ) in magnetic fields were achievable from all BZO-doped samples. The optimally processed YBCO film with 7.5 mol% BZO nanoparticles exhibited the J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> values of 0.39 and 0.5 MA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 77 K in 1 T and at 65 K in 3 T for H//c, respectively. The BZO nanoparticles of 10-50 nm size trapped in the YBCO matrix are considered to be responsible for enhanced flux pinning in BZO-doped YBCO films.

Introducing Artificial Pinning Centers Into YBCO Thin Films to Improve Surface Resistance in a DC Magnetic Field

We investigated the effect of introducing artificial pinning centers (APCs) into YBa2Cu3O7-δ (YBCO) thin films to reduce the microwave surface resistance (Rs) in a high dc magnetic field for high-performance microwave devices with high-quality factor (Q). YBCO thin films with and without APCs were deposited on MgO(100) substrates by using the pulsed laser deposition technique. We used commercial 0, 1.5, 3.0 wt% BaMO3 (BMO, M = Zr, Hf) doped YBCO targets. The δω and δφ of the YBCO thin films increased as BMO doping increased, and the rate of increase appeared to be smaller for BHO doping than for BZO doping. The Rs of these thin films was measured at 21.8 GHz with the dielectric resonator method and a dc magnetic field of up to 5.0 T was applied parallel to the c-axis of the YBCO thin films during the Rs measurements. The Rs of the BMO doped films in the magnetic field was smaller than that of the pure YBCO films. In particular the Rs of the 1.5 wt% BHO doped films was the smallest among all of the films, about half compared with that of the Rs of the pure YBCO films at 4 T and 20 K. As a result, we found that introducing APCs into YBCO thin films is effective for decreasing Rs under a dc magnetic field.

MOD-Derived YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;7-δ&lt;/sub&gt; Thin Films using a Fast Pyrolysis Process

In the present work, a fast pyrolysis process is developed for YBa2Cu3O7-δ (YBCO) films preparation with trifluroacetates metalorganic deposition technique (TFA-MOD). The decomposition of TFA salts as well as the surface morphology of pyrolyzed films is investigated with respect to the pyrolysis temperature and its heating rate. Two typical surface morphologies for the pyrolyzed films, being smooth or buckled, are revealed subjecting to the heating rate and film thickness, which related to the subsequent YBCO films property. Smooth and wrinkle-free pyrolyzed films are achieved by using this fast pyrolysis process with a heating rate as high as 5°C/min. The final crystallized YBCO films exhibit good performances with the superconducting transition temperature of 91 K and critical current density of 2.0 MA/cm2 at 77 K, suggesting a rapid, promising MOD route available for scale-up preparation of YBCO coated conductors.

Preparation of YBa2Cu3O7-δ Patterned Film Using Metal Organic Deposition with Electron Beam Irradiation

A microfabrication method to produce YBa2Cu3O7-δ (YBCO) was investigated using the metal organic deposition (MOD) process with electron beam (EB) irradiation. EB irradiation causes decomposition of the C–H and –COO– bonds and desorption of oxygen atoms in the metal octylate precursors. Therefore, oxidation of metal atoms could become harder for the MOD with EB irradiation than for the conventional MOD because of lack of oxygen, and consequently a longer prefiring time is required to ensure oxidation of the metal atoms. Additionally, the heating rate for crystallization was increased to improve film coverage. Finally YBCO film with superconductivity was successfully obtained.

Optical tuning and ultrafast dynamics of high-temperature superconducting terahertz metamaterials

Abstract Through the integration of semiconductors or complex oxides into metal resonators, tunable metamaterials have been achieved by a change of environment using an external stimulus. Metals provide high conductivity to realize a strong resonant response in metamaterials; however, they contribute very little to the tunability. The complex conductivity in high-temperature superconducting films is highly sensitive to external perturbations, which provides new opportunities in achieving tunable metamaterials resulting directly from the resonant elements. Additionally, superconducting metamaterials are expected to enable strong nonlinear response and quantum effects, particularly when Josephson junctions are integrated into the metamaterial resonant elements. Here we demonstrate ultrafast dynamical tuning of resonance in the terahertz (THz) frequency range in YBa2Cu3O7-δ (YBCO) split-ring resonator (SRR) arrays excited by near infrared femtosecond laser pulses. The photoexcitation breaks the superconducting Cooper pairs to create quasiparticles. This dramatically modifies the imaginary part of the complex conductivity and consequently the metamaterial resonance on an ultrafast timescale, although the real conductivity does not change significantly. We observed resonance switching accompanied by substantial frequency tuning as a function of photoexcitation fluence, which also strongly depends on the nanoscale thickness of the superconducting films. All of our experimental results agree with calculations using an analytical model, which takes into account the contributions of the complex conductivity of the YBCO films to SRR resistance and kinetic inductance. The theoretical calculations reveal that the increasing SRR resistance upon increasing photoexcitation fluence is responsible for the reduction of resonance strength, and changes in both the resistance and kinetic inductance cause the resonance frequency shifts.