Method to extracting the penetration field in superconductors from DC magnetization data

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• The lower critical field (Bc1) is a fundamental property of superconductors, reflecting Cooper pair density.
• Conventional Bc1 determination relies on the DC penetration field (Bp), but lacks a standardized mathematical extraction method.
• Existing Bc1(T) analyses often focus solely on London penetration depth.

Purpose of the Study:

• To develop a robust mathematical routine for extracting the DC penetration field (Bp) from magnetization data.
• To propose a novel method for determining the lower critical field (Bc1) in various superconducting materials.
• To advance Bc1(T) analysis for extracting primary thermodynamic superconducting parameters.

Main Methods:

• Fitting DC magnetization curves (M(Bappl)) to a power law to extract Bp.
• Establishing a threshold criterion (Mc) by convention for Bp determination.
• Applying the method to diverse superconducting samples including polycrystalline, thin films, and single crystals.

Main Results:

• A new method for extracting Bp from magnetization data was successfully developed and validated.
• The method allows for the simultaneous extraction of the power-law exponent.
• Advanced analysis of Bc1(T) data enabled the extraction of key thermodynamic parameters like superconducting energy gap and specific heat jump.

Conclusions:

• The proposed power-law fitting method provides a reliable approach for determining Bc1 and related superconducting properties.
• This technique broadens the scope of Bc1(T) analysis, enabling deeper insights into superconducting thermodynamics.
• The method is applicable across a wide range of superconducting materials, facilitating comparative studies.