Multiferroics, materials that exhibit the unique coupling between magnetism and ferroelectricity, have long been regarded as promising candidates for advanced technologies, from spintronics to energy-efficient memory devices and optical devices. However, their practicality has often been limited by a major constraint: most multiferroic materials lose their functionality at temperatures above room temperature, typically around 20°C. This creates a significant challenge for applications where heat is an inevitable factor, such as in electronic devices or computing systems, where temperatures can easily exceed this threshold.
This limitation has been a key factor hindering the widespread adoption of multiferroics for practical applications, as these materials often become inefficient or non-functional when exposed to higher temperatures, including those generated by devices in operation or during hot summer months. However, recent groundbreaking research conducted by a team at Tohoku University has made a significant leap in overcoming this limitation, revealing a high-temperature multiferroic material capable of retaining its unique functionality at much higher temperatures than previously thought possible.
The Breakthrough Discovery: Tb2(MoO4)3
On December 18, 2024, a study published in the prestigious journal Communications Materials introduced terbium oxide (Tb2(MoO4)3 as a high-temperature multiferroic material. This compound demonstrated the ability to manipulate electric polarization using a magnetic field even at temperatures as high as 160°C, far beyond the traditional limit of around 20°C for multiferroics. This new discovery marks a massive leap forward in the development of multiferroic materials that can operate at higher temperatures, providing new opportunities for technological applications where heat tolerance is crucial.
The Challenges of Multiferroics
The central issue with most multiferroics is the fact that the coupling between magnetism and ferroelectricity—known as the magnetoelectric effect—tends to break down at higher temperatures. This limits their functionality and makes them unsuitable for real-world applications in devices that must perform under a range of conditions. For instance, a multiferroic material that loses its functionality in the heat of summer or due to the operational heat of a device could not be reliably used in spintronics or memory devices, areas where performance at elevated temperatures is critical.
To overcome this challenge, the research team at Tohoku University decided to explore new ways of combining the key functional properties of multiferroics, such as the piezoelectric effect (the coupling between electric polarization and physical strain) and the magnetoelastic effect (the coupling between physical strain and magnetization). By combining these two mechanisms, the researchers were able to activate the magnetoelectric effect—which is the hallmark feature of multiferroics—at high temperatures, well above the threshold previously considered unachievable.
The Role of Piezoelectric and Magnetoelastic Effects
The researchers’ approach involved combining piezoelectric and magnetoelastic effects, which allowed for the magnetoelectric effect to be activated at higher temperatures. The piezoelectric effect involves the coupling between electric polarization and mechanical strain, while the magnetoelastic effect refers to the coupling between physical strain and magnetization. By effectively combining these two effects, the team succeeded in developing a material that could maintain its magnetoelectric coupling at temperatures as high as 160°C, overcoming the typical temperature limitations of multiferroics.
This combination of effects led to a stable, functional high-temperature multiferroic, opening up the possibility for a wide range of future applications in technologies that require energy-efficient, high-temperature performance. According to Shimon Tajima, one of the researchers involved in the study, “This work may pave new avenues for exploring high-temperature multiferroics,” underscoring the far-reaching implications of this breakthrough.
Potential Applications of High-Temperature Multiferroics
The successful demonstration of Tb2(MoO4)3 as a high-temperature multiferroic holds significant promise for a variety of technological applications. Perhaps one of the most exciting possibilities is in the field of spintronics. Spintronics, or spin-based electronics, is a technology that utilizes the intrinsic spin of electrons, in addition to their charge, to encode information. This allows for the development of more efficient and powerful devices, such as memory and logic devices, which consume less power and offer faster processing speeds than traditional electronic systems. The new high-temperature multiferroic material could make spintronics devices more reliable by enabling them to operate effectively at a wider range of temperatures, including in real-world environments where heat may be a factor.
Another promising application lies in energy-efficient memory devices. Traditional memory technologies, such as dynamic random-access memory (DRAM), consume significant amounts of energy to maintain data. However, multiferroics offer the potential for non-volatile memory, meaning they could store data without needing a constant power supply. If these materials can operate at higher temperatures, they could open the door to low-power memory systems that are both energy-efficient and reliable.
Additionally, high-temperature multiferroics may lead to advanced optical devices. The ability to manipulate electric polarization with magnetic fields at elevated temperatures could pave the way for new types of optical modulators, light diodes, or even quantum computing devices that could operate at higher temperatures without losing performance. This could have significant implications for the future of optical communication and quantum technologies, which rely on the manipulation of light and matter.
A New Era for Multiferroics Research
The discovery of Tb2(MoO4)3 as a high-temperature multiferroic material represents a major breakthrough in the field, overcoming one of the biggest hurdles facing multiferroics. By successfully manipulating the magnetoelectric effect at 160°C, researchers have opened up the possibility of multiferroics that can operate at practical temperatures, without the functional loss that has previously plagued these materials.
“This breakthrough could lead to power-saving spintronics devices, advanced optical devices, and more,” says Tajima. As multiferroics become more practical for use in real-world applications, this research may catalyze further advancements in electronics, memory technology, and even quantum computing.
Looking ahead, the discovery of high-temperature multiferroics like Tb2(MoO4)3 could usher in a new era of devices that not only perform better but also consume far less energy. This breakthrough could be a key stepping stone towards more efficient and powerful electronic systems, driving the future of smart technologies, quantum computing, and advanced electronics.
Conclusion
The research team at Tohoku University has made an important step forward in the development of high-temperature multiferroic materials, with their discovery of Tb2(MoO4)3 as a functioning multiferroic at temperatures up to 160°C. This breakthrough removes the key limitation of multiferroic materials, unlocking their potential for use in a variety of applications, from spintronics to memory devices and optical technologies. By combining the piezoelectric and magnetoelastic effects, the researchers have demonstrated that it is possible to stabilize the magnetoelectric effect at higher temperatures, opening the door to a new generation of energy-efficient, high-performance devices. This discovery has far-reaching implications for the future of electronics, offering the promise of power-saving technologies that can operate reliably in a variety of environments.
Reference: Shimon Tajima et al, A high-temperature multiferroic Tb2(MoO4)3, Communications Materials (2024). DOI: 10.1038/s43246-024-00717-8