Magnetism and superconductivity in La0.7Ca0.3MnO3/YBa2Cu3O7−δ superlattices

Abstract

We report on the magnetic and superconducting properties of La 0.7 Ca 0.3 MnO 3 /YBa 2 Cu 3 O 7 ͑LCMO/ YBCO͒ superlattices. For a constant LCMO layer thickness of 6 unit cells ͑u.c.͒, resistance and susceptibility measurements show superconductivity for YBCO layer thickness in excess of 4 unit cells. The critical temperature increases with YBCO thickness, and a T c of 58 K is found for a YBCO thickness of 10 unit cells. Magnetization measurements show a ferromagnetic transition at 100 K in a (LCMO 6 u.c. /YBCO 5 u.c. ͒ 15 bilayer superlattice, and a depressed value of the saturation magnetization of 20 emu cm Ϫ3. These results are discussed in terms of interface disorder ͑analyzed by x-ray diffraction and transmission electron microscopy͒ and of the possible interaction between magnetism and superconductivity.

Spin-dependent magnetoresistance of ferromagnet/superconductor/ferromagnetLa0.7Ca0.3MnO3∕YBa2Cu3

“…[7][8][9] In recent years there has been an increasing interest in structures combining oxide ferromagnets and oxide superconductors. [10][11][12][13][14] In particular, the combination of high-T c superconductors ͑HTS͒ and colossal magnetoresistance materials ͑CMR͒, gives rise to a number of new properties and behaviors, which considerably enrich the study of F / S interplay. 15,16 The unconventional pairing symmetry ͑d-wave͒ of the superconductor with an anisotropic gap exhibiting nodes in ͓110͔ directions, affords quasiparticles to be incorporated at zero energy cost.…”

Spin diffusion versus proximity effect at ferromagnet/superconductorLa0.7Ca0.3MnO3∕YBa2Cu3OPeña1, Visani2, García‐Barriocanal3 et al. 2006Phys. Rev. BSelf Cite541251View full textAdd to dashboardCite

“…[6][7][8][9][10][11][12][13] In many cases the F-S competition is obscured by interface disorder like roughness, interdiffusion, or interface alloying. With the ͑re͒dis-covery of colossal magnetoresistance ͑CMR͒ materials there has been renewed activity in the field with heterostructures involving high-T c superconductors ͑HTSs͒ and CMR materials, [14][15][16][17][18][19] which incorporate a number of interesting new ingredients. ͑1͒ F and S oxides can be chosen with the same crystalline structure, well-matching lattice parameters, and good chemical compatibility, which allows the growth of highly perfect interfaces, despite the larger complexity of these materials as compared to single-element or alloy transition metals.…”

Suppressed magnetization inLa0.7Ca0.3MnO3∕YBa2Cu3O7−

“…Since both classes of materials have very similar perovskite structures with comparable lattice constants in the basal plane, it is possible to combine them into structurally coherent superlattices with very sharp interfaces. 6,7 Previous experiments have already shown that cuprate/manganite based superlattices have distinctively different properties compared to their transition metal counterparts. They exhibit unusually long ranging proximity effects, 8 spin injection into the superconducting layer, 9 and even giant magnetoresistance.…”