Scientists Flip Quantum Effect to Create Magnetism

A team at Osaka Metropolitan University has solved a 50-year physics puzzle and opened a new door for quantum technology in the process.

The researchers discovered that the famous Kondo effect, a quantum phenomenon that typically suppresses magnetism in materials, can actually create magnetism instead. The secret? Changing the size of quantum spins from one-half to one completely flips the effect.

Associate Professor Hironori Yamaguchi and his team built an entirely new type of quantum material using organic molecules and nickel ions. This careful design let them test something physicists have wondered about since 1977: does spin size change how quantum particles behave together?

The answer surprised everyone. In their earlier experiments with spin one-half systems, the Kondo effect locked quantum spins into pairs with zero magnetism, exactly as expected. But when they increased the spin size to one, the same effect suddenly started promoting magnetic order across the entire material.

For decades, textbooks taught that the Kondo effect mainly quiets magnetism by creating what physicists call singlets, where spins pair up and cancel each other out. This discovery rewrites that understanding. Above a certain spin size, the Kondo effect switches roles entirely and becomes a creator of magnetism rather than a suppressor.

The team achieved this by engineering a Kondo necklace model, a theoretical framework proposed nearly five decades ago that was never successfully built in a lab until now. By stripping away the complexity of real materials and focusing purely on spin interactions, they isolated the core physics that drives quantum behavior.

Why This Inspires

This breakthrough matters beyond the physics lab. Being able to flip quantum materials between magnetic and non-magnetic states by controlling just one property gives engineers a powerful new tool for designing quantum devices.

Quantum computers need precise control over how particles interact and entangle. The ability to switch the Kondo effect on and off could help reduce magnetic noise, control quantum states more reliably, and create new types of quantum information processors.

The discovery also reveals something profound about nature: quantum matter has hidden boundaries where tiny changes produce dramatically different collective behaviors. Finding these boundaries helps scientists predict and design new materials with properties we need but don't yet have.

Yamaguchi's team used a molecular design framework called RaX-D that allows atom-level precision in building quantum materials. This same approach could now be applied to engineer other quantum systems with switchable properties.

The researchers are already planning next steps to develop practical quantum materials based on their findings. What started as a fundamental physics question has become a blueprint for quantum technology that could power computers, sensors, and devices we haven't imagined yet.

Sometimes the biggest technological leaps come from understanding the smallest building blocks of matter a little bit better.