Suppressed Magnetization at the Surfaces and Interfaces of Ferromagnetic Metallic Manganites

Abstract

What happens to ferromagnetism at the surfaces and interfaces of manganites? With the competition between charge, spin, and orbital degrees of freedom, it is not surprising that the surface behavior may be profoundly different than that of the bulk. Using a powerful combination of two surface probes, tunneling and polarized x-ray interactions, this paper reviews our work on the nature of the electronic and magnetic states at manganite surfaces and interfaces. The general observation is that ferromagnetism is not the lowest energy state at the surface or interface, which results in a suppression or even loss of ferromagnetic order at the surface. Two cases will be discussed ranging from the surface of the quasi-2D bilayer manganite (La${}_{2-2x}$Sr${}_{1+2x}$Mn${}_2$O${}_7$) to the 3D Perovskite (La${}_{2/3}$Sr${}_{1/3}$MnO${}_3$)/SrTiO${}_3$ interface. For the bilayer manganite, that is, ferromagnetic and conducting in the bulk, these probes present clear evidence for an intrinsic insulating non-ferromagnetic surface layer atop adjacent subsurface layers that display the full bulk magnetization. This abrupt intrinsic magnetic interface is attributed to the weak inter-bilayer coupling native to these quasi-two-dimensional materials. This is in marked contrast to the non-layered manganite system (La${}_{2/3}$Sr${}_{1/3}$MnO${}_3$/SrTiO${}_3$), whose magnetization near the interface is less than half the bulk value at low temperatures and decreases with increasing temperature at a faster rate than the bulk.

15 pages, 13 figures

References in corpus (10)

• Nearly total spin polarization in La2/3Sr1/3MnO3 from tunneling experiments
• The origin of high transport spin polarization in La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$: direct evidence for minority spin states
• Polarons and confinement of electronic motion to two dimensions in a layered transition metal oxide
• Spin-polarized tunneling spectroscopy in tunnel junctions with half-metallic electrodes
• Full Bulk Spin Polarization and Intrinsic Tunnel Barriers at the Surface of Layered Manganites
• X-ray resonant magnetic scattering from structurally and magnetically rough interfaces in multilayered systems I. Specular reflectivity
• Spectacular doping dependence of interlayer exchange and other results on spin waves in bilayer manganites
• Electronic and magnetic properties of the (001) surface of hole-doped manganites
• Surface Magnetic Phase Diagram of Tetragonal Manganites
• Magnetic order and valency at La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$/SrTiO${}_3$ interfaces

Cited by in corpus (13)

• Charge transport and magnetization profile at the interface between a correlated metal and an antiferromagnetic insulator
• Bilayer manganites: polarons in the midst of a metallic breakdown
• Enhancing interfacial magnetization with a ferroelectric
• Magnetic Domain Structure of La0.7Sr0.3MnO3 thin-films probed at variable temperature with Scanning Electron Microscopy with Polarization Analysis
• Element-Specific Depth Profile of Magnetism and Stoichiometry at the La0.67Sr0.33MnO3/BiFeO3 Interface
• Interfacial Magnetism in Complex Oxide Heterostructures Probed by Neutrons and X-rays
• Interfacial Magnetism in Manganite Superlattices
• Magnetism and electronic structure of YTiO${}_3$ thin films
• Transient quantum isolation and critical behavior in the magnetization dynamics of half-metallic manganites
• Composition dependence of electronic, magnetic, transport and morphological properties of mixed valence manganite thin films
• Investigation of ferromagnetic domain behavior and phase transition at nanoscale in bilayer manganites
• Persistent metal-insulator transition at the surface of an oxygen-deficient, epitaxial manganite film
• Electronic and magnetic properties of (1 1 1)-oriented CoCr2O4 epitaxial thin film