X-Ray Microscopy and Nanomagnetism
CXRO has a long history of developing and operating soft X-ray microscopes at the Advanced Light Source. These instruments exploit the natural contrast mechanisms of soft X-rays — near absorption edges of carbon, nitrogen, and oxygen — to image biological, environmental, and materials science specimens at high spatial resolution without the need for staining or sectioning.
CXRO pioneered the use of soft X-ray microscopy and scattering to image magnetic structures at the nanoscale and study their ultrafast dynamics. Leveraging element-specific magnetic contrast through X-ray magnetic circular dichroism (XMCD), our research reveals how nanomagnetic systems behave under applied fields, spin currents, and ultrafast optical excitation.
XM-1 Specifications
| Source | Bend magnet |
| Energy Range | 500–1300 eV |
| Monochromator | Zone-plate linear |
| Spatial Resolution | Typical 25 nm (best 10 nm) |
| Temporal Resolution | 70 ps |
| Field of View | 15 μm single field; larger areas can be tiled |
| Detector | Back-thinned 2048 × 2048 pixel CCD |
| Sample Environment | External magnetic fields up to 5 kOe (beam direction) and 2 kOe (in-plane); He atmosphere; wet or dry |
Microscopy Techniques
Full-Field Transmission X-Ray Microscopy (TXM)
Using Fresnel zone plate objectives, full-field TXM provides real-space images with spatial resolution below 15 nm. Spectral tunability allows element- and chemical-state-specific imaging (NEXAFS microscopy).
Scanning Transmission X-Ray Microscopy (STXM)
STXM raster-scans a focused X-ray probe across the specimen and records transmitted intensity pixel by pixel. This mode is ideal for spectro-microscopy, mapping chemical composition at the nanoscale.
Tomography
Tilt-series acquisition enables 3D reconstruction of specimen structure with isotropic nanometer resolution, providing insights into internal morphology of cells, batteries, and composite materials.
In Situ & Operando Imaging
Custom sample environments enable imaging under controlled conditions — wet cells for biological specimens, electrochemical cells for battery research, and gas-flow cells for catalysis studies.
Nanomagnetism Research
Discoveries in nanoscale magnetics, such as the Giant Magnetoresistance (GMR) effect, have contributed to increasing storage density from megabytes to terabytes per square inch. Fundamentally different ideas are needed to cope with the demand for higher storage density and increased operation speed. Spintronics has emerged as a leading candidate — the ultimate vision is electronics that only utilizes spin currents, which would tremendously reduce energy consumption. Our research aims to unveil the basic physical principles.
Magnetic domain walls are potential building blocks in novel spintronics applications. Their dynamics — how they react to applied forces — determine how they can be used. XM-1’s unique combination of 10 nm spatial resolution and 70 ps temporal resolution enables researchers to view nanoscale dynamics that are challenging or impossible to see in other ways.
Domain Wall Dynamics
Fast oscillations of a trapped domain wall on a 100 nm length scale and sub-nanosecond time scale, captured using XM-1.
Magnetic Domain Imaging
Full-field X-ray microscopy at the L-edges of 3d transition metals provides real-space images of magnetic domains with ~25 nm spatial resolution. CXRO studies domain wall motion, skyrmion lattices, and vortex dynamics in thin films and patterned nanostructures.
Ultrafast Demagnetization
Using time-resolved X-ray techniques synchronized with femtosecond laser pulses, CXRO studies sub-picosecond spin dynamics including all-optical switching and ultrafast demagnetization in magnetic multilayers.
Spin-Orbit Torque Devices
X-ray microscopy enables direct observation of current-driven magnetization switching in spin-orbit torque (SOT) devices, providing insights into switching mechanisms relevant to magnetic memory (MRAM) technology.
Coherent X-Ray Magnetic Imaging
Coherent X-ray techniques such as resonant small-angle X-ray scattering and holography extend magnetic imaging to buried interfaces and provide statistical information about magnetic correlations.
Related Capabilities
Zone plate optics for the microscopes are fabricated by the Nanofabrication group.
