Magnetic field dependence of the copper charge density wave order in a YBa2Cu3O7/Nd-0.65(Ca0.7Sr0.3)(0.35)MnO3 superlattice

Article

关键词: STRIPE ORDER;    SUPERCONDUCTIVITY;    FLUCTUATIONS;    COMPETITION;   

DOI  :  10.1103/PhysRevB.104.174513

来源: SCIE

【 摘 要 】

For a YBa2Cu3O7/Nd-0.65(Ca0.7Sr0.3)(0.35)MnO3 (YBCO/NCSMO) superlattice, we studied with resonant elastic x-ray scattering (REXS) at the Cu L-3 edge how the copper sublattice charge density wave (Cu-CDW) order in YBCO is affected by a large magnetic field up to 6.9 T that weakens the CE-type antiferromagnetic (AF) and the charge/orbital (Mn-CO) orders of the manganite in favor of a ferromagnetic state. While a field of only 2 T induces a strong ferromagnetic moment in the manganite, we find that the Bragg peak of the Cu-CDW hardly changes up to 6 T. Moreover, as the magnetic field is further increased to 6.9 T, the Cu-CDW Bragg peak gets suddenly enhanced and broadened, whereas the ferromagnetic moment of the manganite is already saturated. The observed uncorrelated magnetic field dependence of the charge orders in the cuprate and manganite layers suggests that these orders are not directly coupled across the interface. We rather interpret our data in terms of an indirect coupling via the domain boundaries of the Mn-CO and the related disorder and lattice strain. This interpretation is supported by additional studies of the magnetoelectric response, which provide evidence for a crossover in the dynamics of the Mn-CO in the range between 6 and 7 T, from a low-field state with pinned domains to a high-field state with more mobile and flexible domain boundaries. We attribute the concomitant enhancement and broadening of the Cu-CDW Bragg peak to this crossover.

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