Sustainable SOT-MRAM memory technology could replace cache memory in computer architecture in the future

How much energy is consumed each time we upload an image to social media, which relies on data centers and cloud storage? Data centers currently account for about 1% of global energy consumption, amounting to 200 terawatt-hours of electricity annually. This immense energy demand has driven researchers to explore innovative ways to reduce energy usage.

A team of scientists at Johannes Gutenberg University Mainz (JGU) in Germany has now achieved a significant goal in memory technology in close collaboration with Antaios, a magnetic random access memory company in France. Their innovation, based on Spin-Orbit Torque (SOT) Magnetic Random-Access Memory (MRAM), offers a highly efficient and powerful solution for data processing and storage—a transformative step forward for technologies ranging from smartphones to supercomputers.

“This prototype is one of a kind and could revolutionize data storage and processing. It aligns with global goals to reduce energy consumption and paves the way for faster, more efficient memory solutions,” said Dr. Rahul Gupta, a former postdoctoral researcher at the JGU Institute of Physics, where he supervised the research, and the lead author of the study recently published in Nature Communications.

SOT-MRAM stands out for its superior power efficiency, nonvolatility, and performance compared to static RAM, making it a strong candidate to replace cache memory in computer architecture, for example. This cutting-edge technology uses electrical currents to switch magnetic states, enabling reliable data storage.

However, one key challenge has been to reduce the high input current required during the writing process while ensuring industrial compatibility. This includes maintaining sufficient thermal stability to store the data for over 10 years and minimizing the energy required to perform the storage task.

By exploiting previously neglected orbital currents, researchers at JGU and Antaios have developed a unique magnetic material incorporating elements such as Ruthenium as a SOT channel—a fundamental building block of SOT MRAM—to significantly enhance performance. Their innovation includes:

• an over 50% reduction in overall energy consumption compared to existing memory technologies on an industrial scale;
• a 30% boost in efficiency, enabling faster and more reliable data storage;
• a 20% reduction in the input current required for magnetic switching to store the data;
• the achievement of a thermal stability factor that ensures data storage longevity of more than 10 years.

The secret behind efficient memory

The breakthrough leverages a phenomenon known as the Orbital Hall Effect (OHE), enabling greater energy efficiency without relying on rare or expensive materials. Traditionally, SOT-MRAM relied on the spin property of electrons, where charge current is converted into spin current via the Spin Hall Effect. This process requires elements with high spin-orbit coupling, typically rare and expensive, often environmentally unfriendly, high atomic number materials such as platinum and tungsten.

“In contrast, our approach harnesses a novel fundamental phenomenon by utilizing orbital currents derived from charge currents through the Orbital Hall Effect, eliminating the dependency on costly and rare materials,” explained Dr. Gupta.

Dr. Gupta further explained that by combining this innovative approach with state-of-the-art engineering, the team has developed a scalable and practical solution ready for integration into everyday technology. This research exemplifies how scientific advancements can address some of the most pressing challenges of our time. With global energy consumption steadily increasing, breakthroughs like this highlight the crucial role of technology in creating a more sustainable future.

Successful industrial collaboration

JGU project coordinator Professor Mathias Kläui emphasized his excitement about the successful collaboration with the team of Dr. Marc Drouard at Antaios in France, saying, “I am delighted that this collaborative effort has resulted in this exciting device concept, which is not only fascinating from a basic science point of view but might have implications in industry for Green IT.

“Reducing power consumption by discovering innovative physical mechanisms that allow for the development of more efficient technologies is one of the aims of our research.”