Gigantic ferroelectric polarization and magnetoelectric coupling in a ferrimagnetic oxide CaBaCo4O7
Abstract
From both fundamental and applications points of view, improper ferroelectrics that exhibiting a strong coupling between polarization and magnetic structure are challenging the scientific community. Several multiferroics belonging to that category have been reported; however, they exhibit rather small values of electric polarization combined with low magnetic ordering temperatures. Only the CuO (tenorite), the ordered perovskites LBaCuFeO5 and the Z-type hexaferrites display magnetic ordering temperatures near room temperature, but they all suffer from polarization much smaller than that of proper ferroelectrics. Here, we report a ferrimagnetic cobaltite, CaBaCo4O7, crystallizing in a polar space group, which enters an improper ferroelectric phase below TC = 64 K. Single crystals of CaBaCo4O7 demonstrate the highest polarization value reported among improper ferroelectrics to date, reaching 10 mC/m2 at TC and approaching 16 mC/m2 at 8 K. Moreover a large magnetoelectric coupling coefficient is also evidenced near TC. This result points to routes for exploring new multiferroics among ferrimagnetic phases.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2013
- Bibcode:
- 2013APS..MARM17008M