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ERC Starting Grant for research on novel technology for selectively switching magnetization

Carl Davies, researcher in the HFML-FELIX laboratory and the Institute for Molecules and Materials at Radboud University, has been awarded an ERC Starting Grant to develop a new approach for selectively switching magnetic order in the project entitled “HandShake”. ERC Starting Grants are designed to support excellent researchers at the career stage at which they are starting their own independent research team or programme. Davies’ project will start in January 2024. “This is a wonderful opportunity to develop an idea that I have been thinking about for some time”, Davies says.

Switching magnetization

Digital information plays a central and ubiquitous role within our modern society. Within hard-disk-drives, data is most commonly encoded in the form of “bits” with magnetization pointing up or down (corresponding to ones or zeros). To therefore write data, one needs to switch these magnetic bits from one polarity to the other, most commonly achieved using a strong and localized magnetic field. However, data centers are now struggling to cope with the already-enormous and exponentially-growing amounts of data in the world. There is therefore a very pressing need to develop faster approaches for reversing magnetization with much better energy-efficiency.

In recent years, breakthrough experiments have demonstrated that circularly-polarized femtosecond-long pulses of light can slightly “push” magnetization via the so-called inverse Faraday effect. Depending on the handedness of the light’s corkscrewing electric field, the deflection can act either upwards or downwards. However, the fundamental pathway of energy flow (from light to electrons to spins) is very lossy and restricts the functional usefulness of the push to the sub-picosecond lifetime of the photo-excited electrons. Put simply, this approach is too fast for its own good to switch magnetization.


Davies’ project aims to reveal an alternative and potentially superior method for selectively switching magnetic order, based instead on exploiting vibrations of the crystal lattice. Specifically, the project will explore how circularly-polarized oscillations of the lattice can switch magnetization. “A major advantage of this approach comes from the fact that the crystal lattice – a geometrical network of many different elements - has many different frequencies of resonance, corresponding to so-called optical phonons. By driving these phonons at resonance, the resulting push that acts on the magnetization may even become strong enough to switch it”, Davies explains. “This approach benefits hugely from the longer lifetime of the phonons, which are usually on the order of picoseconds. Moreover, we should be able to steer the direction of the magnetic reversal via the helicity of the chiral lattice vibrations.”

Picture of Carl Davies

New techniques

The characteristic frequencies of optical phonons are invariably found in the infrared spectral range. The project will therefore take advantage of the world-unique free-electron lasers at HFML-FELIX, which deliver highly-tunable and very intense infrared pulses of light. These will serve to pump optical phonons at resonance in a wide variety of materials.

To track the ensuing changes of magnetization in time, a suite of multi-color stroboscopic and single-shot pump-probe techniques will be constructed. This will directly resolve how circularly-polarized phonons can interact with and ultimately switch magnetic ordering. While the challenging and high-risk experiments proposed within “HandShake” explore largely-uncharted physics, they could reveal a disruptive new tool that enables the highly-efficient, ultrafast and directional switching of spontaneous order.

Condensed Matter Physics at HFML-FELIX

Carl Davies is a researcher in the Condensed Matter Physics group, studying how light and matter interact. The goal of the group’s research is to understand and control the relation between properties and structure of nanoscopic and molecular materials, with an emphasis on phenomena that occur on very short time scales. The group is embedded within the international research facility HFML-FELIX. The FELIX free electron lasers generate intense infrared/terahertz radiation with an unprecedented tuning range, providing the world’s most complete coverage of the (far) infrared spectrum. The HFML creates the strongest possible static magnetic fields. This instrumentation is largely unmatched and the opportunities created by combining the strengths of the two coupled laboratories are world-wide unique.


The ERC, set up by the European Union in 2007, is the premier European funding organisation for excellent frontier research. ERC aims to make the European research base more prepared to respond to the needs of a knowledge-based society and provide Europe with the capabilities in frontier research necessary to meet global challenges. ERC Starting Grants are for researchers with 2-7 years of experience since the completion of their PhD, a scientific track record showing great promise and an excellent research proposal. In total, 400 researchers have won this year’s ERC Starting Grants. Read more on the ERC website.

We warmly congratulate Carl with the grant!

Contact information

For more information, please contact

  • Carl Davies, carl.davies [at] (carl[dot]davies[at]ru[dot]nl)
  • HFML-FELIX Communications, mark.zwartkruis [at] (mark[dot]zwartkruis[at]ru[dot]nl)
  • IMM Communications: imm-communication [at] (imm-communication[at]ru[dot]nl)

Contact information

Sustainability, Innovation, Molecules and materials, Science