Mechanical Squeeze Rewires Magnetism in Altermagnets, ORNL Finds

Researchers at Oak Ridge National Laboratory have shown that a small mechanical squeeze can sharply alter the magnetic structure and electrical behavior of altermagnets, a candidate material class for spintronic devices and quantum computing hardware.

The team compressed tiny crystals of manganese telluride and iron sulfide between titanium plates and watched the response with neutron diffraction at ORNL's Spallation Neutron Source. The pressure shifted the relative populations of magnetic domains inside the crystals. It also changed the anomalous Hall effect, an electrical transport phenomenon, giving direct evidence that strain reaches both magnetism and electron motion.

The work, funded through the Department of Energy, appeared in two consecutive studies published in 2026. One paper, in Physical Review X, covers the manganese telluride results. The other, in Advanced Materials, covers the iron sulfide compound. ORNL neutron scientist Feng Ye co-authored both.

Why does strain control matter?

Altermagnets sit at the center of a broader push toward spintronics. Conventional electronics process and store information using the electrical charge of electrons. Spintronics also exploits electron spin, a quantum property that carries magnetic information.

If researchers can find and mature the right host materials, altermagnets among them, the approach could advance technologies from wireless communication to quantum computing. The bottleneck is control. Most tuning methods rely on temperature, magnetic fields or complex device structures. Mechanical strain offers a simpler dial.

"By controlling the magnetic domains, we can directly influence the transport behavior, and that opens the door to exploring these materials for spintronic technologies," said Pengcheng Dai of Rice University, a former neutron scientist at ORNL and senior figure on both papers.

The ORNL results show that the magnetic texture and the electrical response move together under pressure. That coupling is the property device engineers would need in order to write, read or route spin-based signals.

How small is the squeeze?

The experiment itself was deliberately simple. The researchers placed millimeter-scale crystals of MnTe and H-FeS between two titanium plates and applied gentle uniaxial compression. No exotic fabrication, no lithography, no field coils.

Neutron diffraction at the Spallation Neutron Source then revealed what the eye cannot: the strain rebalanced the populations of magnetic domains, regions of the crystal with distinct magnetic arrangements, and simultaneously modified the anomalous Hall effect measured in the material.

"What's exciting is that one creative experimental idea — a small mechanical squeeze between two plates — can reveal entirely new magnetic behavior and push the field forward, and neutron scattering plays such a critical role, revealing the underlying change in magnetism," said Feng Ye.

The finding matters because it demonstrates a low-cost control knob for a material class that remains largely at the physics-exploration stage. Strain engineering is already standard practice in silicon manufacturing, where chipmakers stretch and compress channels to boost transistor speed. Extending that same toolkit to altermagnets gives the field a familiar engineering path.

What was published?

The two journal papers carry distinct findings:

• Physical Review X (2026, vol. 16, issue 3): Zhaoyu Liu and colleagues, including Pengcheng Dai and Feng Ye, reported a strain-tunable anomalous Hall effect in hexagonal MnTe, linking mechanical deformation to electrical transport.
• Advanced Materials (2026, vol. 38, issue 56): Weiliang Yao and colleagues documented uniaxial-strain-tuned magnetism in H-FeS, an altermagnet candidate, with neutron scattering data from ORNL.

Both papers draw on experiments at the Spallation Neutron Source, a DOE Office of Science user facility that remains one of the few instruments worldwide capable of resolving magnetic domain populations inside strained crystals.

The discovery is a physics result, not a product. No device, circuit or timeline for commercialization exists yet. But the demonstration that a mechanical squeeze can rewrite both the magnetic and electrical character of altermagnets gives researchers a practical route toward building blocks for future spintronic devices. If the domain-control effect scales beyond small crystals, strain could become the standard lever for programming altermagnetic materials.