Magnetic signatures of 120 K superconductivity at interfaces in La2CuO4+δ. Issue 5 (22nd January 2020)

• Record Type: Journal Article
• Authors: Choi, Eun-Mi; Zhu, Bonan; Lu, Ping; Feighan, John; Sun, Xing; Wang, Haiyan; MacManus-Driscoll, Judith L.
• Is Part Of: Nanoscale. Volume 12:Issue 5(2020)
• Page Start: 3157
• Page End: 3165
• Publication Date: 2020-01-22
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr04996g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : In self-assembled vertically aligned nanocomposite (VAN) thin films of La2 CuO4+ δ + LaCuO3, we find from DC magnetic susceptibility measurements, weak signatures of superconductivity at ∼120 K. Abstract : In self-assembled vertically aligned nanocomposite (VAN) thin films of La2 CuO4+ δ + LaCuO3, we find from DC magnetic susceptibility measurements, weak signatures of superconductivity at ∼120 K. This compares to a maximum T C of 40 K in bulk La2 CuO4+ δ . The 120 K signature occurs only when both c -axis and a -axis oriented La2 CuO4+ δ grains are present in the films. The superconductivity was lost after 3 months of storage but was recovered by annealing in oxygen. From lattice parameter analyses undertaken close to the c / a grain boundaries, it was determined that expansion of the La perovskite block in c -La2 CuO4+ δ enables the differently oriented grains to join at the interface. This expansion is consistent with the higher T C interfacial region. The work shows a new direction for increasing T C in cuprates – namely careful strain engineering of the crystal structure independently in-plane and out-of-plane.