Energiewende

Abkehr von der Kernenergie, Ausbau von Solar- und Windkraft, Energiegewinnung aus Biomasse, Senkung des Energieverbrauchs. Bis 2050 soll die Schweiz klimaneutral werden. Ein ehrgeiziges Ziel, welches durch die zunehmend herausfordernde geopolitische Lage dringlicher denn je geworden ist. Wie lässt sich in den nächsten Jahren eine nachhaltige und widerstandsfähige Energieversorgung für die Schweiz aufbauen? Wie können erneuerbare Energien optimal genutzt werden? Welche neuen Technologien sind besonders vielversprechend? Am PSI suchen Forschende nach Antworten auf diese entscheidenden Fragen.

Klein et al

RENiO3 Single Crystals (RE = Nd, Sm, Gd, Dy, Y, Ho, Er, Lu) Grown from Molten Salts under 2000 bar of Oxygen Gas Pressure

The electronic properties of transition-metal oxides with highly correlated electrons are of central importance in modern condensed-matter physics and chemistry, both for their fundamental scientific interest and for their potential for advanced electronic applications. However, the design of materials with tailored properties has been restricted by the limited understanding of their structure–property relationships, which are particularly complex in the proximity of the regime where localized electrons become gradually mobile. RENiO3 perovskites, characterized by the presence of spontaneous metal to insulator transitions, are some of the most widely used model materials for the investigation of this region in theoretical studies. However, crucial experimental information needed to validate theoretical predictions is still lacking due to their challenging high-pressure synthesis, which has prevented to date the growth of sizable bulk single crystals with RE ≠ La, Pr, and Nd. Here we report the first successful growth of single crystals with RE = Nd, Sm, Gd, Dy, Y, Ho, Er, and Lu in sizes up to ∼75 μm, grown from molten salts in a temperature gradient under 2000 bar of oxygen gas pressure. The crystals display regular prismatic shapes with flat facets, and their crystal structures and metal–insulator and antiferromagnetic order transition temperatures are in excellent agreement with previously reported values obtained from polycrystalline samples. The availability of such crystals opens access to measurements that have hitherto been impossible to conduct. This should contribute to a better understanding of the fascinating properties of materials with highly correlated electrons and guide future efforts to engineer transition-metal oxides with tailored functional properties.

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