Category Physics

The spin cycloid structure in BiFeO3. Credit: MIPT press-office

Electromagnetic effect allows to control magnetic ‪polarization of a material by applying external electric field. Materials with such properties may be used to develop a new generation of ultra-energy efficient‪ computer memoy . A team proposed a theoretical model that explains the unexpectedly high values of the linear magnetoelectric effect in BiFeO3 (bismuth ferrite) that have been observed in a number of experiments and also suggested a way of further enhancing the effect.

One particular feature of bismuth ferrite is that in bulk samples, spins of Fe3+ iron ions are arranged in the form of a cycloid. This spin structure can be destroyed by a strong magnetic field or mechanical stress...

Glued to the spot: Max Planck scientists from Stuttgart have used gallium as an adhesive to grip a glass sphere with a movable punch model. The metal is located at the bottom of the punch model. Once it touches the glass sphere, the researchers heat the gallium and then cool it off again, so that it connects to the glass. This way, they can retract the sphere from the surface. Credit: © MPI for Intelligent Systems

Researchers are suggesting gallium as just such a reversible adhesive. By inducing slight changes in temperature, they can control whether a layer of gallium sticks or not. This is based on the fact that gallium transitions from a solid state to a liquid state at ~30C...

This diagram shows the standard layout of transistors in cell phone power amplifiers, at left, and a new highly efficient amplifier design, at right. The new design could help make possible next-generation cell phones, low-cost collision-avoidance radar for cars and lightweight microsatellites for communications. Credit: Image courtesy of Purdue University

A new highly efficient power amplifier for electronics could help make possible next-generation cell phones, low-cost collision-avoidance radar for cars and lightweight microsatellites for communications. 5G mobile devices expected around 2019 will require improved power amplifiers operating at very high frequencies...

Black and yellow garden spider (Argiope aurantia). Credit: © leekris / Fotolia

Secret of always-taut spider threads inspires new material. Why doesn’t a spider’s web sag in the wind or catapult flies back out like a trampoline? The answer, according to new research by an international team of scientists, lies in the physics behind a ‘hybrid’ material produced by spiders for their webs.

Pulling on a sticky thread in a garden spider’s orb web and letting it snap back reveals that the thread never sags but always stays taut – even when stretched to many times its original length. This is because any loose thread is immediately spooled inside the tiny droplets of watery glue that coat and surround the core gossamer fibres of the web’s capture spiral.

The researchers studied the details of thi...