PEEM-3 research highlights

The PEEM3 endstation at the Advanced Light Source (ALS) is a world-leading facility for X-ray Photoemission Electron Microscopy. It provides high-resolution spectro-imaging (down to ~50 nm) of the chemical, structural, and magnetic properties of complex materials.

The following research examples, drawn from major publications over the last decade, showcase the unique capabilities of PEEM3 across various scientific disciplines.

1. Biomineralization & Environmental Science

One of the most prolific research areas for PEEM3 is the study of how marine organisms build their skeletons and shells. This work is critical for understanding biological resilience to climate change and ocean acidification.

• Discovery of Transient Mineral Precursors (2024): Researchers used PEEM3’s "Myriad Mapping" technique to identify previously unknown mineral precursors in coral skeletons and mollusk shells. This study revealed that biomineralization is more complex than once thought, involving both amorphous and crystalline transient phases before forming stable aragonite.

  • Major Publication: Nature Communications, 2024 (Gilbert et al.).

• Misorientation Toughening in Corals (2021): By mapping the crystal orientation of individual aragonite fibers, researchers discovered that small misorientations between adjacent crystals are key to the remarkable toughness of coral skeletons and seashells.

  • Major Publication: PNAS, 2021.

• Climate Change Resilience: PEEM3 has been used to show how the crystallization rate of coral skeletons correlates with their ability to withstand ocean acidification, providing a molecular-scale predictor for reef survival.

2. Nanomagnetism & Spintronics

PEEM3 is a powerful tool for imaging magnetic domains and dynamics, utilizing X-ray Magnetic Circular Dichroism (XMCD) to reveal how spin textures evolve at the nanoscale.

• Antiferromagnetic State Differentiation (2023): Using novel "spiraling" X-ray beams (vortex beams), researchers were able to differentiate between degenerate states in an antiferromagnetic lattice—a feat nearly impossible with traditional techniques. This opens new doors for antiferromagnetic spintronics.

  • ALS Science Highlight: April 2023.

• Entropy-Driven Order in "Tetris Ice" (2022): Researchers studied artificial spin-ice arrays patterned into Tetris-like shapes. PEEM3 allowed for the visualization of how local disorder can paradoxically drive long-range order in these nanomagnet arrays, providing insights into the physics of frustrated systems.

  • Major Publication: Nature Physics / ALS Highlight, 2022.

• Magnetization Switching in Microstructures (2024): Recent work has explored how the size and shape of magnetostrictive microstructures affect their ability to switch magnetization in response to applied voltage, advancing the development of energy-efficient memory devices.

3. Complex Oxides & Multiferroics

The ability to apply in-situ electric and magnetic fields makes PEEM3 ideal for studying multiferroic materials, where electrical and magnetic properties are coupled.

• Electric-Field Control of Magnetism: PEEM3 has been instrumental in visualizing the switching of magnetic domains in multiferroic materials like Bismuth Ferrite (BiFeO3) through the application of small electric fields. This research is a cornerstone for the development of future low-power "magnetoelectric" computing.

• Strain-Driven Phenomena: Researchers use the endstation to observe how epitaxial strain in thin-film oxides can "tune" magnetic and electronic phases, enabling the design of materials with tailor-made properties for sensors and actuators.

4. 2D Materials & Surface Chemistry

Beyond magnetism, PEEM3’s high spatial and spectral resolution allows for the characterization of the chemical and electronic landscape of 2D materials and interfaces.

• Interface Magnetism in 2D Heterostructures: By combining PEEM3 with molecular beam epitaxy (MBE), scientists can image the emergence of magnetism at the interface between non-magnetic 2D materials and ferromagnetic substrates.

• Chemical Mapping of Molecular Interfaces: The endstation is used to study the orientation of chemical bonds in organic thin films and molecular interfaces, which is essential for optimizing organic photovoltaics and flexible electronics.

Technical Capabilities Showcase

• Spatial Resolution: Currently reaches 50 nm, allowing for the observation of individual grains and magnetic domain walls.

• Flexible Environment: Sample temperatures from 30 K to 800 K, with the ability to apply in-situ magnetic fields and short current/voltage pulses (up to 7 Amps/400 Volts); sample rotation; chemical reactions (reducing/oxidizing environment using gases up to 6E-6 mbar or higher).

• Polarization Control: Full control over linear and circular X-ray polarization allows for the differentiation of chemical bonds (LD) and magnetic moments (MCD).