Empire State Review Contributor 
In a breakthrough poised to reshape materials science and electronics, researchers have developed an innovative laser-based method that detects ultra-faint magnetic signals in metals traditionally viewed as non-magnetic, including gold, copper, and aluminum. Published on July 19 in Nature Communications, the study finally solves a century-old puzzle in physics by amplifying elusive magnetic “whispers” previously undetectable in common metals.
Since the discovery of the Hall effect over a century ago, physicists have understood that electrical currents can generate magnetic responses. In magnetic metals like iron, these effects are robust and easily measured. But in non-magnetic metals, the equivalent response—known as the optical Hall effect—is extremely weak and has remained experimentally inaccessible at visible light wavelengths.
The team, led by Ph.D. candidate Nadav Am Shalom and Prof. Amir Capua from Hebrew University, in collaboration with Weizmann Institute, Penn State, and University of Manchester, crafted a new approach using magneto-optical Kerr effect (MOKE) spectroscopy. By deploying a 440-nanometer blue laser and modulating a strong external magnetic field, they significantly enhanced the sensitivity of their measurements.
Their refined technique allows the capture of magnetic “echoes” in common metals, including copper, gold, aluminum, tantalum, and platinum—an achievement once deemed nearly impossible. These signals arise from spin–orbit coupling, a quantum interaction between an electron’s motion and its spin, which subtly imparts magnetic behavior even in metals previously considered non-magnetic.
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“It was like trying to hear a whisper in a noisy room for decades,” remarked Prof. Capua, emphasizing the long-standing challenge of measuring these faint effects.
This discovery holds transformative potential for spintronics—a cutting-edge field aiming to harness the intrinsic angular momentum (spin) of electrons for data storage, logic operations, and quantum computing. Traditional electronics rely on electron charge, but spintronics uses both charge and spin, promising devices that are faster, more energy-efficient, and capable of operating at the quantum level.
Non-invasive, laser-based detection of magnetic responses can enable non-contact probing of nanoscale circuits, advanced manipulation of spin currents without relying on large magnetic fields or cryogenic cooling, and precision studies of spin–orbit effects critical to devices like MRAM, spin-wave logic gates, and quantum processors.
Prof. Capua’s team envisions a future where electronic devices are designed and monitored using light, enabling ultrafast, energy-efficient spin-based components.
Beyond electronics, this method offers a new window into fundamental material properties. Non-magnetic metals are ubiquitous across industries, from aerospace to consumer electronics. Gaining deeper insight into their subtle magnetic behavior could drive innovation in next-generation sensors and non-destructive testing, energy-efficient computing architectures, and novel memory technologies with faster switching speeds and lower power consumption.
This breakthrough aligns with parallel academic and industrial momentum. Other teams have employed femtosecond lasers to manipulate spin states in magnetic or antiferromagnetic materials. Yet the advantage of the new method lies in its versatility: it probes non-magnetic substrates without needing cryogenics or electrical contacts—significantly reducing complexity and cost.
Next steps for the research team include refining the technique’s sensitivity and applying it to complex microelectronic circuits and two-dimensional materials like graphene—where spin–orbit effects are strong. They also aim to integrate the system into manufacturing, enabling in-line quality checks and real-time monitoring of spintronic device fabrication.
The potential impact is vast: mainstreamed into consumer electronics, this technology could realize smartphones, laptops, and data centers featuring high-speed, low-power spintronic components—ushering in a new era of sustainable performance. In quantum computing, reliable detection and manipulation of spin states in metals could contribute to more stable qubits and efficient quantum circuits.
By capturing the optical “whispers” of magnetism in gold, copper, and aluminum, this laser spectroscopy technique not only resolves a century-old physics mystery but also lays the groundwork for a revolution in spintronics, quantum technology, and electronic materials science. With this light-based probe, researchers and engineers can explore, design, and deploy devices that combine speed, efficiency, and quantum control—ushering in a new technological frontier.
