A one-dimensional tunable magnetic metamaterial.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Electromagnetism

Background:

• Superconducting metamaterials offer unique electromagnetic properties.
• Josephson junctions, specifically radio-frequency superconducting quantum interference devices (rf-SQUIDs), exhibit nonlinear inductance.
• This nonlinearity allows for external control of device characteristics.

Purpose of the Study:

• To experimentally demonstrate a tunable one-dimensional superconducting metamaterial.
• To investigate the tunability of metamaterial parameters via an applied magnetic field.
• To characterize the effective magnetic permeability of the metamaterial.

Main Methods:

• Fabrication of a one-dimensional metamaterial composed of 54 rf-SQUIDs.
• In situ tuning of the metamaterial's resonance frequency using a DC magnetic field.
• Measurement of the complex transmission coefficient (S₂₁) to determine effective parameters.

Main Results:

• The superconducting metamaterial exhibits tunable properties over a broad frequency band.
• The resonance frequency of the metamaterial is effectively tuned by the applied DC magnetic field.
• The effective magnetic permeability (μr,eff) was successfully extracted using transmission coefficient data.

Conclusions:

• The presented rf-SQUID-based metamaterial demonstrates significant magnetic field tunability.
• This tunable superconducting metamaterial holds potential for applications in frequency-agile devices.
• The method utilizing only the complex transmission coefficient is effective for characterizing such metamaterials.