Magnetoelectric coupling and exchange bias effects in multiferroic NdCrO3

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism and Ferroelectricity

Background:

• The RCrO3 series typically exhibits magnetic ordering but not necessarily ferroelectricity below the Néel temperature (T N).
• Understanding the interplay between magnetic, structural, and electric properties in rare-earth chromites is crucial for novel material development.

Purpose of the Study:

• To investigate the emergence of ferroelectricity in NdCrO3.
• To explore the coupling between magnetic, electric, and structural properties.
• To assess the potential for magnetoelectric applications.

Main Methods:

• Synchrotron X-ray diffraction to determine crystal structure and phase transitions.
• Measurements of electric polarization (P(T)) as a function of temperature.
• Magnetic hysteresis loop measurements.

Main Results:

• Ferroelectricity observed around 88 K, significantly below T N (∼25 K).
• Structural transformation from centrosymmetric Pnma to non-centrosymmetric Pna21 space group linked to ferroelectricity.
• Strong magnetoelectric coupling demonstrated, influenced by magnetic field cooling.
• Evidence of exchange bias effect in both electric polarization and magnetic hysteresis loops.

Conclusions:

• NdCrO3 exhibits ferroelectricity coupled with a structural phase transition below its magnetic ordering temperature.
• A rare co-occurrence of exchange bias in both magnetic and electric properties suggests significant magnetoelectric coupling.
• The findings are of fundamental interest and attractive for technological applications near liquid nitrogen temperature.