Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Nickelates I
TT 5.7: Talk
Monday, March 18, 2024, 11:15–11:30, H 3007
Synthesis of bulk Rare Earth Nickelates from infinite-layer to Ruddlesden-Popper — •Pascal Puphal1, Vignesh Sundaramurthy1, Valentin Zimmermann1, Yu-Mi Wu1, Y. Eren Suyolcu1, Björn Wehinger2, Masahiko Isobe1, Bernhard Keimer1, and Matthias Hepting1 — 1Max Planck Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany — 2European Synchrotron Radiation Facility, 71 Avenue des Martyrs, F-38043 Grenoble, France
Recently, rare-earth nickel oxides have emerged as a new class of unconventional superconductors. Where two types of structures have drawn particular interest. The first type comprises nickelates with the infinite-layer crystal structure which only exists via topochemical synthesis, such as Nd0.8Sr0.2NiO2, showing superconducting transition temperatures Tc up to 20 K. The second type falls in to the Ruddlesden-Popper phase nickelates, where La3Ni2O7 under hydrostatic pressure manifests a remarkably high Curie temperature TC of 80 K. Despite these promising observations, the possibly distinct mechanisms driving the superconductivity in these two types of nickelates are not yet fully understood. In my talk I will show limitations in the doping and ways out of this issue via topochemistry for the first class of nickelates. We recently observed that the second class exhibits multiple crystallographic phases and a pronounced sensitivity to oxygen stoichiometry. Here, I will show how they affect their physical properties and superconducting mechanism.
Keywords: La3Ni2O7; infinite-layer; high-TC; Topochemistry