DQMP Forum - Lucia Varbaro - Cheol Yeon Cheol

14.04.2026 13:00 – 14:00

Magnetic field driven re-entrant superconductivity in infinite layer nickelates
Lucia Varbaro (group of prof. Triscone)

We study the synthesis and electronic behavior of infinite-layer nickelate thin films Nd1−xEuxNiO2
(NENO). The superconducting phase is obtained from perovskite nickelates via topotactic reduction,
removing apical oxygens to form square-planar NiO2. Following W. Wei’s approach, metallic Al is deposited
on NdNiO3 films, driving the reaction 2Al + 3NdNiO3 → Al2O3 + 3NdNiO2. Films are grown by
RF off-axis magnetron sputtering, with in situ Al deposition. High-quality 112 NENO films were achieved
on LSAT and NdGaO3 substrates. The interaction between Eu2+/Nd3+ magnetism and superconductivity
reveals re-entrant behavior and distinct superconducting domes in the Hc2–Tc phase diagram, consistent
with the Jaccarino–Peter effect. Additionally, Hall data are explained by adding an anomalous term linked
to the ions’ paramagnetic response.


Emergent 2D-XY magnetism in monolayer NiPS3
Cheol-Yeon Cheon (group of prof. Morpurgo)

Magnetocrystalline anisotropy is theoretically predicted to have a profound influence on two-dimensional
(2D) magnetism [1,2], including the emergence of non-collinear topological phases, but experimental platform
for investigating such effects has remained scarce. I will present electrical transport measurements
on van der Waals antiferromagnetic NiPS3 and show that the monolayer exhibits magnetic order distinct
from that of thicker layers, revealing the important role of crystal anisotropy in the ultrathin limit and
suggesting a crossover to 2D-XY magnetism [3]. I will then briefly discuss anisotropic magnetoresistance
in ultrathin NiPS3 as a possible route to probe this regime in greater detail in the future.

[1] Jos´e et al., Phys. Rev. B 16, 1217–1241 (1977). [
2] Li, Z.-Q. et al. Phys. Rev. E 101, 060105 (2020).
[3] Cheon et al., Nat Commun 17, 60 (2026).

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre