Author
Anthony Arrott
Other affiliations: Ford Motor Company, ETH Zurich, University of Michigan
Bio: Anthony Arrott is an academic researcher from Simon Fraser University. The author has contributed to research in topics: Magnetization & Magnetic anisotropy. The author has an hindex of 30, co-authored 135 publications receiving 6321 citations. Previous affiliations of Anthony Arrott include Ford Motor Company & ETH Zurich.
Papers published on a yearly basis
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12 Sep 1996
TL;DR: In this paper, the authors introduce the concept of molecular field approximation and the Heisenberg Hamiltonian, and the nucleation problem, as well as the basic micromagnetics.
Abstract: 1.: Introduction. 2.: Molecular field approximation. 3.: The Heisenberg Hamiltonian. 4.: Magnetization vs. temperature. 5.: Anisotropy and time effects. 6.: Another energy term. 7.: Basic micromagnetics. 8.: Energy minimization. 9.: The nucleation problem. 10.: Analytic micromagnetics. 11.: Numerical micromagnetics. References. Index
1,101 citations
1,068 citations
TL;DR: In this article, a criterion for determining the onset of ferromagnetism in a material as its temperature is lowered from a region in which the linearity of its magnetic moment versus field isotherm gives an indication of paramagnetisms.
Abstract: A criterion is proposed for determining the onset of ferromagnetism in a material as its temperature is lowered from a region in which the linearity of its magnetic moment versus field isotherm gives an indication of paramagnetism. Within the limits of validity of a molecular field treatment, the Curie temperature is shown to be in general indicated by the third power of the magnetization being proportional to the internal magnetic field. The method has been employed to redetermine the Curie point of nickel from the data of Weiss and Forrer, of ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$ from the data of Smith and of some alloys from the data of Kaufmann and his collaborators and the author.
1,068 citations
TL;DR: In this paper, a detailed discussion of the underlying physical mechanisms in FMR and SMOKE studies is presented and the temperature and thickness dependences of the perpendicular uniaxial and fourfold in-plane anisotropies are given and discussed.
Abstract: Metastable fcc structures using ultrathin layers of metastable fcc Co(001) and fcc Cu(001) were grown by molecular-beam epitaxy. The growth was studied using reflection high-energy electron-diffraction (RHEED) patterns and RHEED intensity oscillations. The magnetic properties were investigated by employing ferromagnetic-resonance (FMR) and surface magneto-optic Kerr effect (SMOKE) techniques. A detailed discussion of the underlying physical mechanisms in FMR and SMOKE studies is presented. The temperature and thickness dependences of the perpendicular uniaxial and fourfold in-plane anisotropies are given and discussed. The role of lattice strains in magnetic anisotropies is demonstrated. FMR measurements revealed that the magnetic properties of single Co layers are different from those in Co/Cu/Co trilayers becuase of a lattice-strain relaxation in the multilayer samples. The exchange coupling between fcc Co(001) layers separated by a fcc Cu(001) interlayer was studied for several structures. The exchange coupling in Co structures was found to be anisotropic. Hysteresis loops were measured by means of SMOKE. Magnetic-trilayer hysteresis loops are complex. Micromagnetic calculations were carried out to explain their main features.
242 citations
223 citations
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TL;DR: Optical, microscopic and electrical measurements suggest that the synthetic process leads to the growth of MoS(2) monolayer, and TEM images verify that the synthesized MoS (2) sheets are highly crystalline.
Abstract: Large-area MoS(2) atomic layers are synthesized on SiO(2) substrates by chemical vapor deposition using MoO(3) and S powders as the reactants. Optical, microscopic and electrical measurements suggest that the synthetic process leads to the growth of MoS(2) monolayer. The TEM images verify that the synthesized MoS(2) sheets are highly crystalline.
3,088 citations
TL;DR: By applying electric fields, the ability to externally control the properties of magnetic materials would be highly desirable from fundamental and technological viewpoints is demonstrated, particularly in view of recent developments in magnetoelectronics and spintronics.
Abstract: It is often assumed that it is not possible to alter the properties of magnetic materials once they have been prepared and put into use. For example, although magnetic materials are used in information technology to store trillions of bits (in the form of magnetization directions established by applying external magnetic fields), the properties of the magnetic medium itself remain unchanged on magnetization reversal. The ability to externally control the properties of magnetic materials would be highly desirable from fundamental and technological viewpoints, particularly in view of recent developments in magnetoelectronics and spintronics. In semiconductors, the conductivity can be varied by applying an electric field, but the electrical manipulation of magnetism has proved elusive. Here we demonstrate electric-field control of ferromagnetism in a thin-film semiconducting alloy, using an insulating-gate field-effect transistor structure. By applying electric fields, we are able to vary isothermally and reversibly the transition temperature of hole-induced ferromagnetism.
1,879 citations
TL;DR: The theory of critical phenomena in systems at equilibrium is reviewed at an introductory level with special emphasis on the values of the critical point exponents α, β, γ,..., and their interrelations as mentioned in this paper.
Abstract: The theory of critical phenomena in systems at equilibrium is reviewed at an introductory level with special emphasis on the values of the critical point exponents α, β, γ,..., and their interrelations. The experimental observations are surveyed and the analogies between different physical systems - fluids, magnets, superfluids, binary alloys, etc. - are developed phenomenologically. An exact theoretical basis for the analogies follows from the equivalence between classical and quantal `lattice gases' and the Ising and Heisenberg-Ising magnetic models. General rigorous inequalities for critical exponents at and below Tc are derived. The nature and validity of the `classical' (phenomenological and mean field) theories are discussed, their predictions being contrasted with the exact results for plane Ising models, which are summarized concisely. Pade approximant and ratio techniques applied to appropriate series expansions lead to precise critical-point estimates for the three-dimensional Heisenberg and Ising models (tables of data are presented). With this background a critique is presented of recent theoretical ideas: namely, the `droplet' picture of the critical point and the `homogeneity' and `scaling' hypotheses. These lead to a `law of corresponding states' near a critical point and to relations between the various exponents which suggest that perhaps only two or three exponents might be algebraically independent for any system.
1,792 citations
TL;DR: In this article, a review of state-of-the-art synthetic routes for the preparation of magnetic nanoparticles useful for biomedical applications is presented, with a special emphasis on showing the benefits of using nanoparticles.
Abstract: This review is focused on describing state-of-the-art synthetic routes for the preparation of magnetic nanoparticles useful for biomedical applications. In addition to this topic, we have also described in some detail some of the possible applications of magnetic nanoparticles in the field of biomedicine with special emphasis on showing the benefits of using nanoparticles. Finally, we have addressed some relevant findings on the importance of having well-defined synthetic routes to produce materials not only with similar physical features but also with similar crystallochemical characteristics.
1,753 citations
TL;DR: In this paper, the physics of spin transfer torque in magnetic devices are discussed and an elementary discussion of the mechanism and experimental progress in this field is provided, along with a review of theoretical and experimental results.
1,688 citations