Scientific Highlights

Lithium fluoride is an important material which is technologically exploited in spintronics and organic light emitting devices. It turns out that there is a vast difference between the morphologies of ultrathin lithium fluoride grown on the (100) facet of a silver single crystal.  At room temperature dendrites are obtained while at elevated temperature lithium fluoride forms square islands. The system is an interesting model to study the crossover between diffusion limited aggregates and island growth.

A team of the Leibniz Institute for Solid State Research (IFW) from Dresden, Germany, led by Dr Alexey Popov has now demonstrated a record blocking temperature of 28 Kelvin at which the magnetic bistability still survives in a submonolayer of a chemically functionalized species of endofullerenes. In this research, X-ray magnetic circular dichroism measurements at low temperatures and high magnetic field at the X-Treme beam line are crucial. The results pave the way toward using such single-molecule magnets as information carriers or magnetic bits.

This experiment performed at SwissFEL shows how fast we can localize electrons out of an electron gas into correlated, well localized states of a material. It is based on a combined ultrafast x-ray absorption and diffraction experiment on an intermetallic system.

Within this synergetic collaboration, PSI scientists have investigated the correlation between magnetic and electronic ordering in NdNiO3 by tuning its properties through proximity to a ferromagnetic manganite layer. The main outcome is that the stray magnetic field from the manganite layer causes a novel ferromagnetic-metallic (FM-M) phase in NNO. This work demonstrates the utilization of heterostructure engineering for creating novel quantum phases.

The authors demonstrate the stability of ferromagnetic order of one unit cell thick optimally doped manganite (La0.7Ba0.3MnO3, LBMO) epitaxially grown between two layers of SrRuO3 (SRO). LBMO shows ferromagnetism even above SRO Tc. Density Functional Theory calculations help understand the reasons behind this interesting result.

The authors find that an annealing process can create a highly ordered network of two-dimensional line defects at the buried interface between a relaxed film and its substrate. The low dimensional network spacing is directly related to the lattice mismatch and can correspondingly be tuned by the choice of substrate.

The authors find using resonant and non-resonant x-ray diffraction on an x-ray free electron laser that the structural distortion and the underlying electronic structure of the charge density wave in TiSe₂ show different energetics at ultrafast timescales. This indicates that the lattice distortion stabilizes the charge density wave.