Peak effect in single crystal MgB(2) superconductor for H axially c-axis

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Magnesium diboride (MgB2) is a well-known superconductor with a complex phase diagram.
• Understanding the behavior of screening currents under magnetic fields is crucial for superconductor applications.

Purpose of the Study:

• To investigate the phase diagram of MgB2 superconductor using a single crystal.
• To identify and characterize the peak effect in screening currents for magnetic fields applied parallel to the c-axis.

Main Methods:

• Utilized a single crystal of MgB2 for experimental analysis.
• Applied magnetic fields parallel to the c-axis (H || c-axis).
• Measured the local fundamental diamagnetic moment to observe screening current behavior.

Main Results:

• Observed a novel peak effect in the screening current of MgB2 for H || c-axis for the first time.
• Identified a narrow diamagnetic step in the magnetic field regime of 10-13.5 kOe.
• This step transitions to a peak effect at higher fields and a gradual transition at lower fields (H < 10 kOe).

Conclusions:

• The study reveals a new phenomenon, the peak effect, in MgB2 superconductors under specific magnetic field orientations.
• The observed diamagnetic transitions provide insights into the flux pinning mechanisms in MgB2.
• These findings contribute to a deeper understanding of MgB2 superconductor phase diagrams and potential applications.