Hebrew University Detects Magnetic Signals in Metals for Faster Processors

Researchers from Hebrew University, alongside collaborators at Weizmann Institute, Pennsylvania State University, and the University of Manchester, have enhanced the magneto-optical Kerr effect (MOKE) technique using a 440-nanometer blue laser and modulated magnetic fields. This advancement enabled the detection of magnetic signals in non-magnetic metals – including copper, gold, aluminium, tantalum, and platinum – a feat previously considered near-impossible. The technique offers a non-invasive method to explore magnetism, potentially aiding the development of faster processors, more efficient systems, and improved sensors, and builds upon Edwin Hall’s 1881 attempt to measure the effect using light.

Detecting Subtle Magnetism

The researchers upgraded a technique known as the magneto-optical Kerr effect (MOKE), which employs a laser to measure alterations in light reflection caused by magnetism, to enhance its sensitivity. This was achieved by combining a 440-nanometer blue laser with large-amplitude modulation of an external magnetic field, allowing for the detection of magnetic echoes in non-magnetic metals including copper, gold, aluminium, tantalum, and platinum. This represents a significant advancement, as detecting such subtle magnetic responses in these materials was previously considered near-impossible.

Traditionally, measurement of the Hall effect, a pivotal tool in the semiconductor industry and materials science, requires physical attachment of wires to a device, a process that is both time-consuming and challenging, particularly when working with nanometer-sized components. The newly developed approach, however, simplifies this process, requiring only a laser beam directed onto the electrical device, offering a non-invasive method for analysis.

Further investigation revealed that seemingly random noise within the signal was, in fact, patterned and linked to a quantum property called spin-orbit coupling, which connects electron movement to electron spin—a key behaviour in modern physics. This connection also impacts how magnetic energy dissipates within materials, providing insights with direct implications for the design of magnetic memory, spintronic devices, and quantum systems.

The technique offers a highly sensitive tool for exploring magnetism in metals without the need for either massive magnets or cryogenic conditions, and represents a significant advancement on earlier attempts to measure the Hall effect with light, as Edwin Hall’s 1881 efforts were unsuccessful due to the lack of detectable signal strength in silver. The research successfully measured what was once considered invisible by tuning into the appropriate frequency and identifying where to look.

Unlocking Quantum Insights

The study addresses the challenge of detecting tiny magnetic effects in non-magnetic materials, including copper, gold, aluminium, tantalum, and platinum, a feat previously considered near-impossible. The researchers were able to detect magnetic echoes in these metals by upgrading the magneto-optical Kerr effect (MOKE) technique.

Digging deeper, the team found that what appeared to be random noise in their signal was not random at all, but followed a clear pattern tied to a quantum property called spin-orbit coupling, which links electron movement to spin—a key behaviour in modern physics. This connection also affects how magnetic energy dissipates in materials, offering insights relevant to the design of magnetic memory, spintronic devices, and even quantum systems.

The technique offers a non-invasive, highly sensitive tool for exploring magnetism in metals without the need for massive magnets or cryogenic conditions, potentially aiding advancements in areas like faster processors, more energy-efficient systems, and sensors with unprecedented accuracy, and also offers a new approach to what was previously achieved with traditional methods of magnetic metal detection. The current research successfully measured what was once thought invisible by tuning into the right frequency and knowing where to look.

Technological Implications

The research builds upon the established Hall effect, a principle crucial to the semiconductor industry and materials science, by offering a simplified measurement process. Traditional Hall effect measurement necessitates physical attachment of wires to a device, a process that is both time-consuming and challenging, particularly when working with nanometer-sized components, whereas the new technique requires only a laser beam directed onto the electrical device.

The team’s analysis of the signal revealed that seemingly random noise followed a patterned connection to spin-orbit coupling, a quantum property linking electron movement to spin—a key behaviour in modern physics. This connection also impacts how magnetic energy dissipates in materials, providing insights with direct implications for the design of magnetic memory, spintronic devices, and even quantum systems.

The technique’s sensitivity allows for the exploration of magnetism in metals without the need for massive magnets or cryogenic conditions, representing a significant advancement on earlier attempts to measure the Hall effect with light, as Edwin Hall’s 1881 efforts were unsuccessful due to the lack of detectable signal strength in silver. The current research successfully measured what was once considered invisible by tuning into the appropriate frequency and identifying where to look, offering a new approach to magnetic metal detection.