A topological theory of the diabolical points (degeneracies) of quantum magnets is presented. Diabolical points are characterized by their diabolicity index, for which topological sum rules are derived. The paradox of the missing diabolical points for Fe8 molecular magnets is clarified. A new method is also developed to provide a simple interpretation, in terms of destructive interferences due ...

Show that the force between hemispheres in the left figure is the same as that between one such hemisphere and either a perfectly conducting plate, or a plate of infinite magnetic permeability. This problem was inspired by e-discussions with J. Castro Paredes. The force between two rectangular-prism permanent magnets has been deduced in [1]. For cylindrical magnets, see [2, 3], and for spheres,...

Preliminary spectroscopy measurements of Al-Al2Ox-Pb tunnel junctions doped with single molecule magnets J. R. Nesbitt Department of Physics, University of Florida Tunnel junctions have been fabricated in which the insulating barrier of Al-Al2OxPb have been doped with single molecule magnets. Low frequency resistance measurements show that the molecules are present in the insulating barrier. Th...

We use the High Current Experiment (HCX) to study three mitigation measures: a rough surface to reduce electron emission and gas desorption from ions striking walls near grazing incidence, a suppressor electrode after the magnets to block beam-induced electrons off the end structures from drifting upstream, and clearing electrodes to remove electrons from drift regions between magnets. We find ...

In a standard insertion device, such as a wiggler or undulator, the force between two rows of magnets increases exponentially as the gap between the rows decreases. This force is usually managed by a powerful mechanical gap adjustor, sometimes with the aid of springs at small values of gap. This paper is a description of how the magnetic forces can be nulled using auxiliary counterforce magnets.

A 4600 Hz fast ramping synchrotron is explored as an economical way of accelerating muons from 4 to 20 GeV/c for a neutrino factory. Eddy current losses are minimized by the low machine duty cycle plus thin grain oriented silicon steel laminations and thin copper wires. Combined function magnets with high gradients alternating within single magnets form the lattice we describe. Muon survival is...

Atomic interdiffusion between FePt and Fe3O4 nanoparticles in annealed FePt-based nanocomposite magnets has been studied by means of structural and magnetic characterizations. The results show that the Fe3Pt phase is formed during the annealing only when the mass ratio x of Fe3O4/FePt is larger than 1/20. When x 1/20, only FePt single phase is formed. It is interesting to find that the coercivi...

A common coil design concept for 2-in-1 superconducting accelerator magnets is presented. It practically eliminates the major problems in the ends of high field magnets built with either high temperature superconductors (HTS) or conventional superconductors. Racetrack coils, consisting of rectangular blocks built with either superconducting tapes or cables, are common to both apertures with eac...

Materials based on metallic elements that have d orbitals and exhibit room temperature magnetism have been known for centuries and applied in a huge range of technologies. Development of room temperature carbon magnets containing exclusively sp orbitals is viewed as great challenge in chemistry, physics, spintronics and materials science. Here we describe a series of room temperature organic ma...

The LHC, a 7 Tev proton collider presently under construction at CERN, requires 1232 superconducting (SC) dipole magnets, featuring a nominal field of 8.33 T inside a cold beam tube of 50 mm inner diameter and a magnetic length of 14.3 m. To achieve such high fields whilst retaining the wellproven fabrication methods of cables made with NbTi superconductors, it is necessary to operate the magne...