Anisotropic Imprint of Amorphization and Phase Separation in Manganite Thin Films via Laser Interference Irradiation

Abstract

Materials with mesoscopic structural and electronic phase separation, either inherent from synthesis or created via external means, are known to exhibit functionalities absent in the homogeneous counterparts. One of the most notable examples is the colossal magnetoresistance discovered in mixed-valence manganites, where the coexistence of nano- to micrometer-sized phase-separated domains dictates the magnetotransport. However, it remains challenging to pattern and process such materials into predesigned structures and devices. In this work, a direct laser interference irradiation (LII) method is employed to produce periodic stripes in thin films of a prototypical phase-separated manganite Pr0.65 (Ca0.75 Sr0.25 )0.35 MnO3 (PCSMO). LII induces selective structural amorphization within the crystalline PCSMO matrix, forming arrays with dimensions commensurate with the laser wavelength. Furthermore, because the length scale of LII modification is compatible to that of phase separation in PCSMO, three orders of magnitude of increase in magnetoresistance and significant in-plane transport anisotropy are observed in treated PCSMO thin films. Our results show that LII is a rapid, cost-effective and contamination-free technique to tailor and improve the physical properties of manganite thin films, and it is promising to be generalized to other functional materials.

Strong Magnetic Anisotropy of Epitaxial PrVO3 Thin Films on SrTiO3 Substrates with Different Orientations

“…The preferential direction of magnetization in thin films is mainly determined by the magnetic anisotropy, which includes shape anisotropy, magnetoelastic anisotropy, and magnetocrystalline anisotropy. There have been numerous studies in the past to explore magnetic anisotropy in other competitive complex systems such as manganites, − and ruthenates, , and because of tunneling magnetoresistance properties of the former, they are being used as magnetic tunneling junction devices. However, little is known of the magnetic anisotropy in vanadium oxide thin films, especially PVO, and thus has yet to be understood.…”

ZnO Nanorods on a LaAlO3–SrTiO3 Interface: Hybrid 1D–2D Diodes with Engineered Electronic Properties

“…Similar metallic interfaces have also been reported in other combinations of insulators like LaTiO 3 /STO, LaVO 3 /STO, LaFeO 3 /Sm 2 CuO 4 , GdTiO 3 /STO, and Al 2 O 3 /STO . Such perovskite oxide thin films and heterostructures have been intensively investigated for novel physical properties and potential applications . On another forefront of materials research, 1D nanostructured materials like nanowires and nanorods (NRs) exhibit unique optical, electrical, and mechanical functionalities, and their dimensionality enables applications extending from probe microscopy tips to interconnections in nanoelectronics.…”

Threshold Dependence of Deep- and Near-subwavelength Ripples Formation on Natural MoS2 Induced by Femtosecond Laser

“…The fact that the bandgap broadens as the number of layer decreases may lead to variations of threshold fluences and ripple periods, since broader bandgap makes harder phonton absorption and thus a reduction of the excited carriers for the same incident fluence and the role of substrate may also not be neglected (for example, fs laser induced subwavelength ripples on SiO 2 have a direction parallel to polarization 7 ), which requires large-area, high-quality thin samples for systematic further study to precisely know the thickness dependence. In addition, our simple effective method (one irradiated spot with many ripple lines) for fabricating small regular structures could lead to anisotropy to physical properties of the in-plane symmetric 2D MoS 2 with the directions along and perpendicular to the ripple lines and related function modifications, as very recently achieved in transition-metal oxides 39 . This promising application issue is a subject to further explorations.…”