Materials that help the phone do not need to be charged

Japanese and Chinese scientists have found that electronics-making materials consume very little energy, mobile phones made of this material may not need to be charged.

According to Phys, a research group at Hiroshima University, Japan, a way to create electric current at room temperature without wasting energy or needing an external power source is due to a material called "topological insulator." ".

Previous studies have shown that electric current can be generated by ferromagnetic properties or high magnetic sensitivity of materials without the need for external power. This phenomenon was first discovered in the 1980s, named "Quantum Hall Effect" (Edwin Hall, according to the American physicist who discovered the effect, Edwin Hall).

However, to achieve the requirement to generate electricity without losing energy, the system still needs to be placed in a very cold environment with a large external magnetic field so far.

The principle of generating electric current on the surface and along the edges of the new material.(Photo: Hiroshima University).

To solve this problem, Japanese scientists used ferromagnetic topological insulating materials , which have the formula "Cr (Sb / Bi) 2Te3" (Cr: Crom, Coll: Antimony, Te: Tellurium, Bi: Bismuth). This material has metallic properties in the outer shell, and insulation in the inner layer. A small thin film made from this material will emit an electric current on the surface or along the edges without an external power source.

In 2007, when they first observed this phenomenon at low temperatures without losing energy, the scientists were surprised. They could not explain why it became a ferromagnetic material from which to generate electricity itself.

"This is why we chose this material as a research object , " said Professor Akio Kimura, Hiroshima University, a member of the research team.

In the Cr (Sb / Bi) 2Te3 compound, Cr is ferromagnetic, acting as a small, atomic-sized magnet. Normally, these atoms will interact to orientate in the North-South direction, but due to the molecular structure of Cr (Sb / Bi) 2Te3, Cr atoms are too far apart to accomplish this. However, the researchers found that non-magnetic atoms such as SB or Te will act as a bridge for this interaction to occur, making the whole material ferromagnetic. This finding is very important in the development of low-power electronic devices.

Currently the results are only achieved at very low temperatures, the team is looking for ways to increase this magnetic phase transition temperature.

"We hope that this achievement will be a prerequisite for creating new materials that work at room temperature in the future," Kimura said. The study was published in Nature Communication on November 19, 2015.