Volume 96, Issue 10, 15 November 2004
Index of content:
- MAGNETISM AND SUPERCONDUCTIVITY (PACS 74-76)
Quasiparticle charge imbalance, first-order phase transition and quantum criticality in ferromagnet∕superconductor∕ferromagnet double-tunnel junctions96(2004); http://dx.doi.org/10.1063/1.1804247View Description Hide Description
Spin-dependent transport in ferromagnet∕superconductor∕ferromagnet double-tunnel junctions is revisited by taking both the spin and quasiparticle charge imbalances into account. It is shown that even a small quasiparticle charge imbalance can lead to remarkable changes of the superconducting and transport properties. In particular, it is found that a first-order phase transition from an inhomogeneous superconducting state to the normal state will take place in both the antiparallel and parallel alignments of magnetizations, as the bias voltage is increased to a critical value. A quantum critical point is specified.
Analysis of the magnetic anisotropy induced by applying a magnetic field during the quenching process in amorphous ribbons96(2004); http://dx.doi.org/10.1063/1.1798402View Description Hide Description
The magnetic anisotropy induced in amorphous magnetic ribbons by applying a magnetic field to the melt during the solidification process is analyzed. Using a model based on the magnetization curve and on the evolution of the uniaxial torque with the applied magnetic field, the volume fractions of the sample affected by the different magnetic anisotropies are obtained for the ribbons of composition and . The results are compared with those obtained in the ribbons of the same composition but with anisotropies induced by the static magnetic annealing. From these results, the different sources of the field-quenching-induced magnetic anisotropy in those amorphous magnetic ribbons are analyzed.
96(2004); http://dx.doi.org/10.1063/1.1805718View Description Hide Description
We report on magnetic and structural properties of - and -type layers implanted with , , and . The samples were subsequently annealed in a atmosphere at a constant temperature in the range between 700 and . Measurements of the magnetization as a function of magnetic field as well as of the temperature show typical paramagnetic behavior. In addition, a weak antiferromagnetic coupling between the implanted ions was observed. 3d-metal rich precipitates of crystalline nature are revealed by high resolution transmission electron microscopy.
96(2004); http://dx.doi.org/10.1063/1.1803634View Description Hide Description
incorporates only as a metallic element and is an Invar material with valence electron concentration 8.67. We have studied the equation of state up to of particles below and above the Curie temperature (room temperature and , respectively) to search for a softening associated with a magnetovolume instabilities characteristic of Invar-type material. The isothermal bulk modulus of particles at room temperature was found to be about 13% smaller than that of the value at . This difference is comparable with the relative difference in the bulk modulus of Invar in a similar temperature range around the Curie temperature.