Anisotropy studies in microstructured Ce-115 heavy fermion superconductors

We recently uncovered the nematic character of a field-induced state in the heavy-fermion superconductor CeRhIn₅, emerging at magnetic fields above 30 T and temperatures below 2 K [1]. The in-plane conductivity develops a sudden anisotropy ρ_a/ρ_b at low temperatures, which is linked to the magnetic field orientation. This raises questions on the role of magnetic ordering in determining the magnetotransport anisotropy. The 4f-moments of CeRhIn₅ order anti-ferromagnetically, while in the related superconductors CeCoIn₅ and CeIrIn₅ no static magnetic order appears. We systematically investigate the anisotropic magnetotransport in sub-micron sized transport devices fabricated using Focused Ion Beam machining from highest-quality single crystals. We present a comparative analysis of the magnetoresistance anisotropy in Ce(Co,Rh,Ir)In₅, and experimentally investigate the role of electronic layeredness in these superconductors.
[1] Ronning, F. et al. Nature 548, 313–317 (2017)