Superconducting Quantum Interference Devices (SQUID) Open Up Practical Applications For Superconductivity

Devices sensitive enough to detect and measure minute changes of magnetic fields, called superconducting quantum interference devices (SQUIDs), are opening up practical application of superconductivity outside the laboratory. Some applications that can benefit from using SQUIDs are magnetically levitating (maglev) trains, earthquake detectors, and even solar power cells.

Dutch physicist Heike Kamerlingh Onnes discovered superconductivity in 1911 during an experiment involving mercury and liquid helium. When a material's temperature is reduced to a certain threshold, its electrical resistance falls down to zero and the expulsion of its magnetic fields occur. Materials that can achieve superconductive are metals and ceramic materials.

The temperature at which superconductivity occurs vary from material to material. Mercury, for example, achieves superconductivity when its temperature is lowered to 4.1K.

Without electrical resistance, an electric current can persist indefinitely even without a power source. There is no power loss with superconductors and that any existing power in a superconductive wire will forever flow in it. Superconducting wires can conduct much larger currents than ordinary wire which create much more intense magnetic fields around them.

Magnetic Resonance Imaging (MRI) machines, mass spectrometers, and even particle accelerators like the Large Hadron Collider use superconducting magnets (electromagnets made from coils of superconducting wires.).

Last year, a research team at the University of Toronto induced high temperature superconductivity in a semiconductor by just using ordinary scotch tape.

Conductive Liquid Cement Developed From Mayenite and CO2 Laser Beam Heating

Researchers from the Japan Synchrotron Radiation Research Institute/SPring-8 in collaboration with scientists from Finland, Germany, and the United States have created liquid cement that has the conductive properties of metal. SPring-8 is a synchrotron radiation facility located in Japan and is operated by the Japan Synchrotron Radiation Research Institute.

Cement is a substance that sets and hardens independently. It helps bind other materials together such as it does with concrete when it is combined with limestone, granite, or sand.

The recent discovery means that this type of conductive liquid cement can lead to semi-conductors that have low energy loss and is easy to mold into different shapes and configurations. Possible applications in electronics for this material can be developed in LCD monitors, protective coatings, and even in computer chips.

Hunting Down Charge Density Waves To Solve High Temperature Superconductivity Mystery

Inside a clean room, physicists Ivan Bozovic (left) and Anthony Bollinger, Brookhaven, work on the molecular beam epitaxy system that produced the atomically perfect materials used in the study.
Credit: Brookhaven National Lab

Scientists are trying to unlock the mystery of high temperature superconductivity (HTS) by studying fluctuations (ripples of moving electrons) called charge density waves (CDW).

Objects or materials that have been super-cooled or its temperature lowered below a certain value, it achieves superconductivity. Temperatures required to achieve superconductivity usually are close to absolute zero (0 Kelvin). This means that there is no electrical resistance and there is an expulsion of magnetic fields occurring at that temperature.

This expulsion is a quantum mechanical property that is described by the Meissner effect.

As the temperature is lowered, the electrical resistance goes down as well. Below a critical temperature, the electrical resistance of a superconductor lowers down to zero. Without it, an electric current can persist indefinitely even without a power source. There is no power loss and that any existing power in a superconductive wire will forever flow in it.

Last September 2012, a team from the University of Toronto induced high temperature superconductivity in a semiconductor just by using Scotch tape. A first for physics.

Recently, researchers have developed HTS materials that would help them understand this phenomenon by recreating it and studying fluctuations within the material called charge density waves.

High Temperature Superconductivity Achieved Using Ordinary Scotch Tape

University of Toronto physics professor Ken Burch with experimental apparatus and tape.
Credit: Diana Tyszko, Faculty of Arts & Science University of Toronto

Superconductivity occurs when objects or materials that are super cooled or cooled below a certain temperature achieves no (zero) electrical resistance and expulsion of magnetic fields. Required temperatures usually approaches absolute zero. This phenomenon is quantum mechanical in nature and is characterized by the Meissner effect.

The Meissner effect is an expulsion of a magnetic field from a superconductor during its transition to the superconducting state.

The electrical resistance of a material slowly goes down as temperature is lowered. When it is cooled below its critical temperature, a superconductor's resistance drops to zero. Without any electrical resistance, an electric current can persist indefinitely even without a power source. Simply put, there is no power loss with superconductors and that any existing power in a superconductive wire will forever flow in it.

University of Toronto led team induces high temperature superconductivity in a semiconductor with Scotch tape

An international team led by University of Toronto physicists has developed a simple new technique using Scotch poster tape that has enabled them to induce high-temperature superconductivity in a semiconductor for the first time. The method paves the way for novel new devices that could be used in quantum computing and to improve energy efficiency.

"Who would have thought simply sticking things together can generate entirely new effects?" said team leader and U of T physicist Ken Burch. High-temperature superconductors are materials that conduct electricity without heating up and losing energy at liquid nitrogen temperatures. They are currently in use for transmitting electricity with low loss and as the building blocks of the next generation of devices (quantum computers).