The IEEE Magnetics Society is the premiere organization for professionals in magnetics research and technology.
Magnetite, Fe3O4, guided early explorers towards unknown frontiers. Since those days, oxides have been the backbone of many scientific and technological developments. When high temperature superconductors were discovered, the subsequent enthusiasm stimulated an impressive development in oxide thin film growth technologies and a deep revision of the understanding of metal oxides and strongly correlated electronic systems. Today, oxides are fueling the discovery and development of unexpected, intriguing, and fascinating new areas of knowledge, such as magnetic ferroelectrics and magnetic monopoles. Ferromagnetic oxides are finding their way as active components in spintronics, either as spin filters for advantageous magnetic tunnel junctions or used to manipulate spins in non-magnetic materials, which could eventually lead to energy-efficient pure spin-current devices. The tiny spin-orbit coupling interaction, responsible for the magnetic anisotropy, has emerged as a toy that allows us the modulation of the transport properties, not only in metallic ferromagnetic systems, but also in antiferromagnetic metals and insulators. This may lead to a new generation of magnetic memory. “Interface is the device” and interfaces between oxides and metals, and interfaces between large band-gap oxides, have led to the discovery of emerging properties such as switchable “on-off” magnetization, by applying suitable electric fields, or magnetism and superconductivity in confined two-dimensional electron gas systems, which challenge our current understanding of oxides.
This is the playground in which we fortunately play, learn, and imagine the future while enjoying building a new science out of the good old oxides. In the lecture, we will travel through the new materials and ideas that make this journey possible and so successful.
This presentation reviews the motivation, history, and recent progress in nanoscale strain-mediated multiferroics. Research descriptions include analytical and experimental work on strain-mediated multiferroic thin films, single magnetic domain structures, and superparamagnetic particles. The results indicate efficiencies orders of magnitude superior to STT approaches and presents a new approach to control magnetism. Discussions of future research opportunities and novel applications are included.
The recent interest on the magnetization reversal process of novel families of nanowires originates in the need to have full information about their magnetic properties for different functionalization and technological applications. The electrochemical route to fabricate nanowires is attracting much interest owing to their low-cost and reliability to fabricate tailored magnetic nanowires and nanotubes. This technique enables the synthesis of nanowires with cylindrical symmetry in opposition to nanostripes prepared by lithography techniques. Arrays of such nanowires can be grown with diameter of 15 to 200 nm, and length from 100 nm up to tens of microns. Cylindrical nanowires can be also grown with compositional multisegmented character and with controlled modulation in diameter intended to play a similar role as notches in lithography nanostripes. The particular study of Co-based nanowires is relevant since their magnetocrystalline anisotropy, in opposition to Py nanostripes, plays an important role to determine the magnetization reversal mechanism by vortex or transverse domain walls and spin rotation modes.
Most thin magnetic films have their magnetization lying in the plane of the film because of shape anisotropy. In recent years there has been a resurgence of interest in thin magnetic films which exhibit a magnetization easy axis along the surface normal due to so-called Perpendicular Magnetic Anisotropy (PMA). PMA has its origins in the symmetry breaking which occurs at surfaces and interfaces and can be strong enough to dominate the magnetic properties of some material systems. In this talk I explain the physics of such materials and show how the magnetic properties associated with PMA are often very well suited to applications. I show three different examples of real and potential applications of PMA materials: ultralow power STT-MRAM memory devices for green computing, 3-dimensional magnetic logic structures and a novel cancer therapy.
Magnetic nanowires can have many names: bits, sensors, heads, artificial cilia, sensors, and nano-bots. These applications require nanometer control of dimensions, while incorporating various metals and alloys. To realize this control, 7- to 200-nm diameter nanowires are synthesized within insulating matrices by direct electrochemistry. Our nanowires can easily have lengths 10,000x their diameters, and they are often layered with magnetic and non-magnetic metals as required by each application. This talk will reveal synthesis secrets for nm-control of layer thicknesses, even for difficult alloys, which has enabled studies of magnetization reversal, magneto-elasticity, giant magnetoresistance, and spin transfer torque switching. These nanowires will mitigate the ITRS Roadmap’s “Size Effect” Grand Challenge which identifies the high resistivities in small interconnects as a barrier to continued progress along Moore’s Law (or better). High magnetoresistance is also possible in other multilayered nanowires that exhibit excellent properties for mulit-level nonvolatile random access memory. If the insulating growth matrix is etched away, the nanowires resemble a magnetic bed of nano-seaweed which enables microfluidic flow sensors and vibration sensors. Finally, we have incubated various nanowires with several healthy and cancerous cell lines, and find that they are readily internalized. Careful magnetic design of these “nano-bots” enables external steering, nano-barcode identification, and several modes of therapy.
New means of urban transportation and logistics will become realistic with superconducting magnetic bearings using bulk high temperature superconductors. The advantage of super¬con-ducting magnetic levitation is that it works passively stable without any electronic control but with attracting and repelling forces to suspend a vehicle pendant or standing upright from zero to high speed - perfect conditions for the idea of rail-bound individual transport with cabins for 4 - 5 passengers requested call by call. They will levitate noiseless over the track made of RE permanent magnets saving energy and travel time. A big step forward to this vision has been made in Dresden. The world largest research and test facility for transport systems using HTS bulk material in the levitation and guidance system in combination with a permanent magnet track was put into operation. A vehicle for 2 passengers, equipped with linear drive propulsion, non-contact energy supply, second braking system and various test and measurement systems is running on an 80 m long oval driveway. In the presentation the principle of superconducting levitation by flux pinning in high temperature supercon¬ductors will be described. Based on this an overview of the SupraTrans II research facility and future directions of super¬conductivity-based magnetic levitation and bearing for automation technology, transportation and medical treatment under enhanced gravity will be given
Lectures on current research in various areas in magnetics.