title: Novel magneto-luminescent effect in LSMO/ZnS:Mn nanocomposites at near-room temperature.
abstract: We report the tuning of the internal Mn photoluminescence (PL) transition of magnetically-ordered Sr-doped lanthanum manganite (LSMO)/Mn-doped zinc sulfide (ZnS:Mn) nanocomposites (NCs) by applying a static magnetic field in the range of 0-1 T below the critical temperature of ∼225 K. To do that, we have systematically fabricated LSMO/ZnS:Mn at different concentrations (1:1, 1:3, 1:5 and 1:10 wt%) via a straightforward solid-state reaction. X-ray diffraction and Raman analyses reveal that both phases coexist with a high degree of crystallinity and purity. Electron microscopy indicates that the NCs are almost spherical with an average crystal size of ∼6 nm, and that their surfaces are clean and smooth. The bifunctional character of LSMO/ZnS:Mn was evidenced by vibrating sample magnetometry and PL spectroscopy analyses, which show a marked ferromagnetic behavior and a broad, intense Mn orange emission band at room temperature. Moreover, the LSMO/ZnS:Mn at 1:3 wt% exhibits magneto-luminescent (ML) coupling below 225 K, and reaches the largest suppression of Mn-band PL intensity (up to ∼10%) at 150 K, when a magnetic field of 1.0 T is applied. The ML effect persists at magnetic fields as low as 0.2 T at 8 K, which can be explained by evoking a magnetic-ordering-induced spin-dependent restriction of the energy transfer to Mn states. No ML effect was observed in bare ZnS:Mn nanoparticles under the same experimental parameters. Our findings suggest that this NC can be considered as a new ML compound, similar to FeCo/InGaN-GaN and LSMO/ZnO NCs, useful as q-bits for quantum computation. The results presented here bring forth new avenues to better understand the interaction between semiconductors and perovskites, and exploit their synergistic effects in magneto-optics, spintronics and nanoelectronics.
authors.affiliation: Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA. Department of Physics, University of Puerto Rico, San Juan, PR 00936, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Beltran-Huarac
authors.forename: Daysi
authors.initials: D
authors.lastname: Diaz-Diestra
authors.forename: Mohammed
authors.initials: M
authors.lastname: Bsatee
authors.forename: Jingzhou
authors.initials: J
authors.lastname: Wang
authors.forename: Wojciech M
authors.initials: WM
authors.lastname: Jadwisienczak
authors.forename: Brad R
authors.initials: BR
authors.lastname: Weiner
authors.forename: Gerardo
authors.initials: G
authors.lastname: Morell