Researchers From Quantum Detection Develop a Method to ­Precisely Analyze Ultrathin Magnetic Layers

Whether hard drives, magnetic tapes, or storage media in data centers – in electronic data processing, information is still stored on magnetic materials and read out electrically. But increasing demands on data processing call for faster, more energy-efficient, and more compact storage technologies. Researchers from ­Leibniz IPHT and the University of Jena, together with TU Chemnitz and TU Bergakademie Freiberg, have developed an innovative method that could help advance the development of more powerful memory – especially for photonic data processing.

The future of data storage may lie in magnetic materials only a few nanometers thick. These often consist of special metal alloys such as cobalt–iron (CoFe) or cobalt–iron–boron (CoFeB), which possess particularly stable magnetic properties. They are already used in modern storage technologies and read out electrically, but are difficult to analyze optically.

“To further develop memory technologies, we need to understand exactly how these materials behave during optical readout,” explains Prof. Dr. Heidemarie Krüger, head of the Quantum Detection research department at Leibniz IPHT and professor at the University of Jena. The challenge: existing measurement methods only work when the magnetic layers are fully aligned – a condition rarely achieved in practice. Krüger’s team has now found a solution.

Light as a Measuring Tool

The researchers use an optical technique to study the interaction of light with the magnetic layers. They apply so-called vector magneto-optical generalized ellipsometry (VMOGE) – a method that uses light reflection to precisely determine the magneto-optical ­properties of magnetic layers.

“Light tells us how the magnetization behaves in the layer – without needing to fully magnetize the material,” Krüger explains. “Most importantly, we can determine the magneto-optical coupling coefficient. This gives us crucial information about the magneto-optical properties of the material.”

Using this method, the magneto-optical properties of unsaturated ferromagnetic materials can be precisely measured for the first time. This could significantly advance the development of giant magnetoresistance (GMR) and tunnel magnetoresistance (TMR) memories for photonic data processing. The optical analysis enables targeted optimization of memory in terms of speed, energy efficiency, and compactness.

Potential for More ­Sustainable Storage

“Our method helps to optimize materials so they consume less energy and work faster,” says Krüger. A more precise analysis of magnetic layers could not only improve existing memory technologies but also enable new architectures – such as components that combine magnetism and light to create even more efficient storage media.

The research team is now working to further develop the method and adapt it to different material systems, Krüger reports. “We’re testing various combinations to find out which are best suited for future applications in photonic data processing.”

Original publication: https://doi.org/10.1088/1361-6463/ad415c