Sapoti: X-ray microscopy’s new frontier at Sirius

Designed to achieve resolutions on the order of 1 nanometer, the Sapoti station of the Carnaúba beamline combines cryogenics, ultra-high vacuum, and cutting-edge mechatronics engineering to reveal structures at the atomic scale

Sapoti (Scanning Analysis by PtychO for Tomographic Imaging) is one of the two experimental stations of the Carnaúba beamline at Sirius. The facility is one of the most sophisticated and challenging stations ever developed at the Brazilian accelerator. Its goal is to achieve resolutions on the order of 1 nanometer in coherent X-ray imaging and tomography, a performance that places it among the world’s most precise instruments in synchrotron light-based microscopy.  

The experimental stations of the Carnaúba beamline

The Carnaúba beamline operates in the 2.05 to 15 keV energy range, and was designed to perform simultaneous measurements with multiple X-ray analytical techniques, including diffraction, spectroscopy, fluorescence, and luminescence, as well as two- and three-dimensional imaging. It is the longest line at Sirius and uses a highly bright beam from an undulator, exploring the full potential for coherence and intensity that a fourth-generation synchrotron light source can provide.

Its infrastructure houses two complementary experimental stations. The Tarumã station was designed for in situ, in vivo (with plants), and cryogenic experiments, operating in an open environment with high flexibility for different types of samples. Sapoti operates in ultra-high vacuum and cryogenic conditions, which ensures even greater thermal and mechanical stability, leading to better spatial resolutions, as well as better conditions for experiments at the lower energy limit.

Read more on the Sirius website

Image: Part of the Carnaúba beamline’s infrastructure at Sirius. The beamline features two experimental stations located 136 and 142 m from the X-ray source, a vertically polarized undulator

Credit: Sirius

Transparent conductive oxide water etching revealed by operando spectroscopy

Perovskite transition metal oxide thin films exhibit a wide range of functional properties that make them promising candidates for electronic devices. In their transparent conductive oxide (TCO) form, they possess a unique combination of high electrical conductivity and visible-range optical transparency. Among the TCOs, SrVO3 (SVO) has gained significant attention due to its electrical and optical properties comparable to the most commonly used indium-tin-oxide (ITO), which suffers from high costs due to the scarcity of indium. However, SVO is prone to surface chemical degradation over time, which poses a significant challenge. This degradation leads to the segregation of Sr towards the surface and the over-oxidization of V, resulting in the formation of a thin insulating layer at the TCO surface. A full understanding and control of these issues are needed to overcome its use in large-scale technology.

In our study we have used pulsed laser deposition (PLD) technique to deposit polycrystalline SVO film of few tens nanometers on top of a Si substrate, which is also suitable for further industrial transfer. To simulate the aging process, we subjected the SVO films to ex situ annealing treatments in air at 200°C, a well-established procedure Subsequently, we performed spectroscopic measurements using x-ray photoemission and x-ray absorption techniques under ultra-high vacuum conditions to characterize the samples. All spectroscopic characterizations were carried out at the APE-HE beamline of Elettra, partly in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MUR Italy Progetti Internazionali) facility.

Read more on the Elettra website