By Chee-Sung Park
Chee-Sung Park’s research interests include investigating on the dialectic, ferroelectric, piezoelectric, and magnetoelectric materials for sensors, actuators, motors, and other functional devices. Currently, his researches have been focused on the functional magnetoelectric devices.
In order to understand magnetoelectric (ME) effect and its fundamental phenomena, his research started from controlling connectivity using various processing methods from thin film to bulk scales. As shown in Fig. 1, various-typed ME structures using two or three phases have been created in his research.
Based on these composites, we are trying to find out (i) how does strain transfer? and (ii) how much strain is transferred?
Another interest is controlling the ME properties as we wish. For actual ME applications, broadband or wideband ME behaviors are necessary to obtain the constant output. Figure 2(a) shows a schematic diagram of ideal wideband ME response in both DC and AC magnetic biases. By understanding strain transfer and controlling the geometric shape, we achieved a near broadband ME response as a function of DC magnetic bias, as shown in Fig. 2(b). Further, a wideband behavior corresponding to the AC magnetic field was successfully demonstrated as shown in Fig. 2(c). Based on this prototype wideband ME composite, further research is conducted to achieve a flat-shaped wideband ME response.
His ultimate goals of ME research are to enhance ME properties which are sensing pTesla values of magnetic field. Currently, he reaches a near pTesla sensible ME composite, as shown in Fig. 3. The sensitivity of pTesla value will be shown in the near future. All interests are still ongoing in the investigation to achieve ultra-high sensitive ME composite devices.