Aspects on the synthesis of infinite-layer nickelate thin films and related transport properties.

Preziosi D., Krieger G., Versini G., Viart N.
  Venerdì 16/09   09:00 - 13:30   Aula D - Marianna Ciccone   II - Fisica della materia   Presentazione
In the last three decades, motivated by a theoretical prediction, several efforts were devoted at achieving an orbital engineering in nickelate heterostructures. The goal was to mimic the electronic structure and conduction properties of cuprates. Finally, these efforts led to the realization of superconducting $Nd_{0.8}Sr_{0.2}NiO_{2}$ infinite-layer thin films below $15 {K}$ with a $Ni\mbox{-}3d^{9-\delta}$ configuration and reduced dimensionality. The main step to achieve this result is an oxygen de-intercalation of the pristine perovskite $Nd_{1-{x}}Sr_{x}NiO_{3}$ phase via a topotactic reduction by using a $CaH_{2}$ powder as a reagent. Existing challenges regarding the synthesis of Sr-doped nickelate thin films, combined with the pivotal handling of the topotactic reduction, make it hard to establish a reproducible route towards superconducting infinite-layer nickelates. This explains why, so far, the zero-resistance state could be reproduced by only few groups. Here, we will report on our synthesis approach to stabilize the infinite-layer phase together with anisotropic magnetotransport measurements, and briefly discuss a novel approach to obtain the infinite-layer phase.