Spin-Driven Multiferroic Properties of PbMn7O12 Perovskite

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Perovskite materials are known for their diverse physical properties.
• Understanding the interplay of charge, orbital, and spin degrees of freedom is crucial for novel material discovery.
• High-pressure synthesis can unlock unique material phases and properties.

Purpose of the Study:

• To synthesize PbMn7O12 perovskite under high-pressure and high-temperature conditions.
• To investigate the structural, magnetic, dielectric, and ferroelectric properties of PbMn7O12.
• To explore the potential of PbMn7O12 as a spin-driven multiferroic material.

Main Methods:

• High-pressure (6 GPa) and high-temperature (1373 K) synthesis.
• X-ray diffraction for structural analysis.
• Magnetic susceptibility, specific heat, dielectric, and pyroelectric measurements.
• Polarization and magnetodielectric effect measurements.

Main Results:

• PbMn7O12 crystallizes in space group R3̅ near room temperature, transitioning to Im3̅ at 397 K (charge ordering).
• Structural modulation associated with orbital ordering occurs below 294 K.
• Two magnetic transitions observed at TN1 = 83 K and TN2 = 77 K, with a possible lock-in transition at TN3 = 43 K.
• Electric polarization develops at the TN2 magnetic transition, confirming PbMn7O12 as a spin-driven multiferroic with polarization ~4 μC/m².
• A small magnetodielectric effect of -1.3 to -1.7% was observed at 10 K and 90 kOe.

Conclusions:

• PbMn7O12 is a novel spin-driven multiferroic perovskite synthesized under extreme conditions.
• The material exhibits complex structural and magnetic phase transitions driven by charge, orbital, and spin ordering.
• The observed coupling between magnetic and electric properties highlights its potential for advanced electronic applications.