Temple University in the United States and the University of Maryland researchers found a new type of magnet, when placed in a magnetic field, the volume will expand, and in the process of collecting energy waste heat to negligible. This new discovery has great potential, not only is expected to replace the existing technology, but also to create a new application.
Temple University Mechanical Engineering Department Director, materials genome science and quantum devices laboratory is responsible for Hashi Deep Chopra and the University of Maryland Department of materials science and engineering professor Manfred Utig published in 21 "natural" magazine published their research results. "Our findings fundamentally changed our understanding of a particular type of magnet that has been known since 1841," Chopra said."
In nineteenth Century 40 's, the British physicist James Jawer discovered that when being placed in a magnetic field, the iron - based magnetic material will change their shape, but the volume remains constant. This phenomenon is known as the "Joule magnetostrictive", since the discovery of the 175 years, all the magnets have shown this feature.
"We have found a new class of magnets, which we call a non Joule magnetostrictive magnet. In the magnetic field, the volume of their volume has changed dramatically." Chopra said, "and, these non - Joule magnetostrictive magnets also have the extraordinary ability to collect or convert energy with minimal heat loss."
Chopra and Ukrainian Teague will specific iron-based alloy placed in the furnace heated to about 760 degrees Celsius, and continued for 30 minutes and then quickly cooled down to room temperature, then to the performance of the material the non Joule magnetostriction behavior.
They found that after heat treatment of the material contains never before seen tiny honeycomb structure, which is they behave non Joule magnetostriction responses of key in a magnetic field. Teague added: "it is known that this unique structure will allow researchers to develop new materials with the same characteristics."
The researchers point out that the conventional magnets can only be used as an actuator in a direction for the force exerted by the joule. Even if only in two directions to move, but also need a large number of bulky magnets, which will increase the volume, reduce efficiency. While the non Joule magnetostrictive magnets can be expanded at the same time, it is easy to realize the compact omnidirectional actuator.
Due to the characteristics of these new magnet is also energy-saving, they can be used to create an extremely low heat loss of a new generation of sensors and actuators, application in the fields of aerospace, automotive, bio medicine, national defense, space exploration, and robotics.
The researchers also said that this new type of magnet does not contain rare earth elements, which can replace the existing expensive but mechanical properties of rare earth based magnetostrictive materials.