Topic
Colossal magnetoresistance
About: Colossal magnetoresistance is a research topic. Over the lifetime, 3658 publications have been published within this topic receiving 130104 citations.
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TL;DR: In this article, the sign and amplitude of the giant magnetoresistance (GMR), AMR, and EHE signal can be tuned by adjusting the Tb-Co layer composition in a spin valve structure.
Abstract: Tb-Co ferrimagnetic alloy thin films and spin valves have been grown to study their magnetoresistance response in various geometries. The studied Tb-Co alloys show strong perpendicular anisotropy and tunable magnetization by several orders of magnitude. Magnetoresistance signals such as giant magnetoresistance (GMR), anisotropic magnetoresistance (AMR), extraordinary Hall effect (EHE), and magnon magnetoresistance (MMR) have been studied. The angular dependence of those magnetoresistive effects is also investigated. Finally we demonstrate that by adjusting the Tb-Co layer composition in a spin valve structure, the sign and the amplitude of the GMR and EHE signal can be tuned.
46 citations
TL;DR: The effect of TiO2 doping on the structure and magnetic and magnetotransport properties of La0.75Sr0.25MnO3 (LSMO)∕xTiO2 has been investigated in this paper.
Abstract: The effect of TiO2 doping on the structure and magnetic and magnetotransport properties of La0.75Sr0.25MnO3 (LSMO)∕xTiO2 has been investigated. These studies show that at low doping level (x⩽2) TiO2 mainly goes into the grain-boundary region, but at high doping level (x⩾3), some part of the TiO2 goes into the perovskite lattice substituting Mn in LSMO and the remainder segregates as a separate phase at the grain boundaries. Results also show that the TiO2 doping has an important effect on a low-field magnetoresistance. In the magnetic field of 8000Oe and at 77K a magnetoresistance value of ∼20% was observed for the composite with a TiO2 doping level of x=2.
46 citations
TL;DR: The success of the correction of spherical aberration in the electron microscope has revolutionized our view of oxides as discussed by the authors, which is a very important class of materials that is promising for future applications of some of the most intriguing phenomena in condensed matter physics.
Abstract: The success of the correction of spherical aberration in the electron microscope has revolutionized our view of oxides. This is a very important class of materials that is promising for future applications of some of the most intriguing phenomena in condensed matter physics: colossal magnetoresistance, colossal ionic conductivity, high Tc superconductivity, and ferroelectricity. Understanding the physics underlying such phenomena, especially in low dimensional systems (thin films, interfaces, nanowires, nanoparticles), relies on the availability of techniques capable of looking at these systems in real space and with atomic resolution and even beyond, with single atom sensitivity; in many cases, the system properties depend on minuscule amounts of point defects that alter the material’s properties dramatically. Atomic resolution spectroscopy in the aberration-corrected electron microscope is one of the most powerful techniques available to materials scientists today. This article will briefly review some state-of-the-art applications to oxide materials: from atomic resolution elemental mapping and single atom imaging to applications to real systems, including oxide interfaces and mapping of physical properties such as the spin state of magnetic atoms.
46 citations
TL;DR: In this paper, the magnetotransport characteristics of Fe∕MgO∕Fe epitaxial tunnel junctions are reported and the main parameter to optimize for device application, namely the output voltage, remains relatively low.
Abstract: The magnetotransport characteristics of Fe∕MgO∕Fe epitaxial tunnel junctions are reported. For clean Fe∕MgO interfaces, a tunnel magnetoresistance of 150% is measured. However, the magnetoresistance decreases rapidly with the applied voltage. Consequently, the main parameter to optimize for device application, namely the output voltage, remains relatively low. This limitation has been solved by interface engineering through the insertion of carbon impurities at the Fe∕MgO interface. Although the tunnel magnetoresistance amplitude is slightly reduced, its variation versus the applied voltage becomes strongly asymmetric with large magnetoresistance maintained up to 1.5V. This determines a large increase of the tunnel junction output voltage.
46 citations
TL;DR: The first observation of giant magnetoresistance was made on iron-chromium superlattices with nearly perfect crystallinity, which was grown by molecular beam epitaxy (MBE) as discussed by the authors.
Abstract: Publisher Summary Magnetoresistance (MR) is the change in electrical resistance of a material in response to a magnetic field. All metals have an inherent, albeit small, MR owing to the Lorentz force that a magnetic field exerts on moving electrons. Although earlier studies reported unusual magnetoresistive effects in layered structures, it was discovered that the application of magnetic fields to atomically engineered materials known as magnetic superlattices greatly reduced their electrical resistance, that is, superlattices had a giant magnetoresistance. Superlattices are a special form of multilayered structures, artificially grown under ultrahigh-vacuum conditions by alternately depositing on a substrate several atomic layers of one element, say, iron, followed by layers of another, such as chromium. The original observation of giant magnetoresistance was made on iron–chromium superlattices with nearly perfect crystallinity, which was grown by molecular beam epitaxy (MBE). Giant magnetoresistance observed in layered and granular structures arises from the dependence of the resistivity on their internal (local) magnetic configuration.
46 citations