Université de Fribourg

Backfolded acoustic phonons as ultrasonic probes in metal-oxide superlattices

Lyzwa, Fryderyk ; Chan, A. ; Khmaladze, Jarji ; Fürsich, K. ; Keimer, B. ; Bernhard, Christian ; Minola, M. ; Mallett, Benjamin P. P.

In: Physical Review Materials, 2020, vol. 4, no. 4, p. 043606

Ultrasonics have been an incisive probe of internal interfaces in a wide variety of systems ranging from stars to solids. For thin-film structures, however, ultrasound is largely ineffective because the signal is dominated by the substrate. Using confocal Raman spectromicroscopy, we show that multiple reflection of sound waves at internal interfaces of a metal-oxide superlattice generates...

Université de Fribourg

Granular superconductivity and charge/orbital order in YBa 2 Cu 3 O 7 /manganite trilayers

Khmaladze, Jarji ; Sarkar, Subhrangsu ; Soulier, Mathias ; Lyzwa, Fryderyk ; Prada, R. de Andres ; Perret, Edith ; Mallett, Benjamin P. P. ; Minola, M. ; Keimer, B. ; Bernhard, Christian

In: Physical Review Materials, 2019, vol. 3, no. 8, p. 084801

We studied how the electronic, superconducting, and magnetic properties of YBa2Cu3O7/Nd1−x(Ca1−ySry )xMnO3 multilayers depend on the tolerance factor and the hole doping of the manganite. In particular, we investigated the granular superconducting state and the related magnetic-field-driven insulator-to- superconductor transition that was previously discovered in corresponding multilayers...

Université de Fribourg

Coupled Cu and Mn charge and orbital orders in YBa₂Cu₃O₇/Nd 0.65 (Ca 1-y Sr y ) 0.35 MnO₃ multilayers

Perret, Edith ; Monney, Claude ; Johnston, S. ; Khmaladze, Jarji ; Lyzwa, Fryderyk ; Gaina, Roxana ; Dantz, M. ; Pelliciari, Jonathan ; Piamonteze, C. ; Mallett, B.P.P. ; Minola, M. ; Keimer, B. ; Schmitt, Thorsten ; Bernhard, Christian

In: Communications Physics, 2018, vol. 1, no. 1, p. 45

The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity. In bulk YBa2Cu3O7−δ the Cu-CDW is incipient and mainly pinned by defects. Nevertheless, a large magnetic field can induce a true long-range Cu- CDW order as it suppresses superconductivity. An enhanced Cu-CDW order was also ...