With the increasing digitization on the global scale, researchers are now focusing on minimizing the energy consumed by electronic devices by searching for methods to manipulate material properties with minimal energy loss. The magnetoelectric (ME) effect in multiferroic materials allows magnetic properties to be controlled by an electric field instead of current, potentially enabling the development of ultralow-power magnetic memories and spintronic devices.

To date, research has been mainly focused on ferroelectric multiferroics, whose electric polarization P can be flipped by applying an electric field E to influence their magnetism. However, the potential of pyroelectrics in the static ME effect remains unexplored. Unlike in ferroelectrics, the P in pyroelectric materials is fixed and cannot be switched by modulating the E. This limitation creates a new degree of freedom—the relative direction between E and P. The electric field can be applied “parallel” or “antiparallel” to the electric polarization. We hypothesize that this overlooked feature can be harnessed to control magnetism through a mechanism distinct from the conventional ME effect.

To test this hypothesis, we selected the pyroelectric ferrimagnet CaBaCo₄O₇ as the model system. We prepared a single crystal and measured its magnetization under various applied electric and magnetic fields. As shown in our infographic, when E is applied parallel to P, the ferrimagnetic order becomes more robust, and the transition temperature T_C increases. Conversely, when E is antiparallel to P, the ferrimagnetic order weakens and T_C decreases. This result demonstrates that in a pyroelectric magnet, the stability of a magnetically ordered phase can be systematically controlled by changing the direction of the applied electric field.

This phenomenon reflects a new type of ME effect unique to pyroelectric materials. This result suggests that the vast family of pyroelectrics, once considered less interesting for this application, can be utilized to design novel functional materials. Our study provides new guidelines for material exploration and opens an exciting and unexplored route toward realizing next-generation energy-efficient electronic devices.

(Written by T. Shirasaki on behalf of all the authors)

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