Dielectric materials be categorized into four types depending on the hysteresis loops they exhibit: paraelectric (PE), ferroelectric (FE), relaxor ferroelectric (RFE), and antiferroelectric (AFE).
Ferroelectric hysteresis loop (left) and magnetic hysteresis loop (right) measured at room temperature indicate the coexistence of ferroelectricity and ferromagnetism. Disclaimer: AAAS and EurekAlert!