Major industries such as modern microelectronics are based on the interaction between matter and electromagnetism. Electromagnetic signals can be processed and stored in specially tailored materials.
Prof. Andrei Pimenov in his Lab
In materials science, electric and magnetic effects have usually been studied separately. There are, however, extraordinary materials called “multiferroics”, in which electric and magnetic excitations are closely linked. Scientists at the Vienna University of Technology (TU Wien) have now shown in an experiment that magnetic properties and excitations can be influenced by an electric voltage. This opens up completely new possibilities for electronics at high frequencies.
The Best of Two Worlds
It has been well known for a long time that electricity and magnetism are two sides of the same coin. Waves in free space, such as visible light or mobile phone radiation, always consist of both an electric and a magnetic component. When it comes to material properties, however, electricity and magnetism have been viewed as separate topics. There are materials with magnetic ordering, which react to magnetic fields, and there are materials with electric ordering, which can be influenced by electric fields.
A magnet has a magnetic field, but no electric field. In a piezoelectric crystal, on the other hand, electric fields can be generated, but no magnetic fields. Having both at the same time seemed impossible. “Usually, both effects are created in very different ways”, says Professor Andrei Pimenov (TU Vienna). “Magnetic ordering comes from electrons aligning their magnetic moments, electric ordering comes from positive and negative charges moving with respect to one another.”
In this material, many electrons align their magnetic moments at low temperatures. Each electron has a magnetic direction which is slightly distorted with respect to the adjoining electron – therefore the electrons create spiral of magnetic moments. The spiral has two possible orientations – clockwise or counterclockwise – and, surprisingly, an external electric field can switch between these two possibilities.
Vibrating Atoms, Wobbling Moments
In magneto-electric materials, the charges and the magnetic moments of the atoms are connected. In dysprosium manganese oxide, this connection is particularly strong: “When the magnetic moments wobble, the electric charges move too”, says Andrei Pimenov. In this material, magnetic moments and electric charges simultaneously play a part in the excitation, and therefore both can be influenced by one single external field.
The effect can be demonstrated by sending terahertz radiation through the material: The polarization of the terahertz beam is changed if the multiferroic material exhibits magnetic ordering. If the magnetic spiral in the material can be switched with an electric field, this electric field eventually determines, whether the polarization of the terahertz beam is being rotated.
There are many ideas for future applications: Wherever it is desirable to combine the respective advantages of magnetic and electric effects, the new magneto-electric materials could be used in the future. This could lead to new kinds of amplifiers, transistors or data storage devices. Also, highly sensitive sensors could be built with electromagnon technology.Further Information:
Florian Aigner | EurekAlert!
From ancient fossils to future cars
21.10.2016 | University of California - Riverside
Study explains strength gap between graphene, carbon fiber
20.10.2016 | Rice University
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering