Takumi Shirasaki

Abstract We investigate the effects of Fe and Sr doping on the magnetoelectric properties of CaBaCo ₄ O ₇ , a multiferroic polar magnet. Substituting Fe at Co sites extends the temperature and field ranges of magnetoelectric responses, transforming the material from pyroelectric to ferroelectric. Similarly, Sr doping at Ca sites induces structural changes that expand the antiferromagnetic phase without altering Co valence. These results demonstrate that impurity doping effectively optimizes the magnetoelectric properties of CaBaCo ₄ O ₇ , offering a promising strategy for enhancing the performance of polar magnetic materials.

We demonstrate a new type of magnetoelectric effect in the pyroelectric ferrimagnet CaBaCo4O7—modulating its phase stability depending on the relative direction between the electric field and its electric polarization, enabling new material design strategies.