Ankit Negi holds a PMN-PT crystal. Standing with him is study co-author Hwang Pill Kim. Photo: NC State.
Ankit Negi holds a PMN-PT crystal. Standing with him is study co-author Hwang Pill Kim. Photo: NC State.

A new study by researchers at North Carolina State University (NC State) has shed light on how electric fields can be used to alter the thermal properties of ferroelectric materials, allowing engineers to manipulate the flow of heat through these materials. Ferroelectric materials are used in a wide variety of applications, from ultrasound devices to memory storage technologies.

“Our work here is a significant advance because we worked with large sample sizes and provide detailed information on the relationship between the type of electric field being applied to the ferroelectric material and the thermal response in the material,” says Jun Liu, an associate professor of mechanical and aerospace engineering at NC State and corresponding author of a paper on this work in Advanced Materials. “In practical terms, this allows users to tune the thermal behavior of the material by applying different electric fields – using alternating current (AC) or direct current (DC) – which paves the way for developing new techniques for managing the flow of heat through various devices.”

For this study, the researchers worked with a ferroelectric material called PMN-PT, a compound of lead, magnesium, niobium, titanium and oxygen that is used in technologies such as sensors, actuators and ultrasound devices. To reflect real-world conditions, the researchers worked with 2.5mm-thick samples of the material at room temperature.

The researchers applied electric fields of varying strengths to the material using both AC and DC sources. Other variables in their testing were the frequency of the current and the length of time that the material was exposed to the electric field. They then used a suite of methods to measure how each sample’s thermal properties changed in response to the different electric field conditions.

The researchers found that all four variables – the strength of the field, whether it was AC or DC, time and frequency – played a role in how the electrical field altered the material’s thermal properties.

“Having a detailed understanding of how each of the four variables influences the material’s thermal properties gives us a significant amount of control in engineering the material’s thermal behavior,” says Ankit Negi, a PhD student at NC State and first author of the paper.

“We’re hoping to establish a similarly detailed understanding of the relationship between electric fields and thermal characteristics for other ferroelectric materials,” Liu says. “And we are open to collaborations on how this work could inform the development of new applications.”

This story is adapted from material from North Carolina State University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.