Superconductivity

* Work on Worksheets* Superconductivity Lecture* Video “Race for Absolute Zero”

Some material from Dr. Tim Lynch

Funded by: HTS State Outreach Centers: DE-PS36-03GO93001-11

Connection with what you know.

Three types of bonds:– Covalent– Ionic – Metallic You remember

Name: Voltage = current X resistance– Ohm’s Law

Where does the resistance energy – Resistance lost as heat

Superconductivity is an exciting field of physics! (Picture below is the levitation of a magnet above a cooled superconductor, the Meissner Effect, )

Source: University of Oslo, Superconductivity Lab

Definition and Research Aim

• Superconductivity is • the flow of electric current without resistance • in certain metals, alloys, and ceramics • at temperatures near absolute zero,

– Research Aim: Get to temperatures hundreds of degrees above absolute zero = -273ºK. (at least to liquid nitrogen temperatures)

• Net: Keep it cold and resistance is zero.

Comparisons of TemperaturesTemperatures F C K water boils 212.0 100.0 373.2 body temp 98.6 37.0 310.2 room temp 77.0 25.0 298.2 water freezes 32.0 0.0 273.2 mercury freezes -37.8 -38.8 234.4 dry ice -108.4 -78.0 195.2 liquid Oxygen -297.4 -183.0 90.2 liquid Nitrogen -320.8 -196.0 77.2 liquid Helium -452.1 -269.0 4.2 absolute zero -459.7 -273.2 0.0

                                                                                             

The Discovery

Discovery by Onnes … zero resistance on a Hg wire at 4.2 K in 1911.

At 4.2K, the Electrical Resistance (opposition of a material to the flow of electrical current

through it)Vanished, Meaning Extremely Good Conduction of Electricity-Superconductivity

Source: A Teacher's Guide to Superconductivity for High School Students

The Key of Superconductivity

Superconductors have the ability to conduct electricity without the loss of energy.

When current flows in an ordinary conductor, for example copper wire, some energy is lost.

As much as 50% lost Cooling it down the resistance is lost

In Simpler Terms…

Source: Oxford University

Shaking the jungle gymKeeps children from movingQuickly through the gym

Cooper Pair: Two electrons that appear to "team up“

– Despite the fact that electrons have a negative charge and normally repel each other.

Below the superconducting transition temperature, paired e- form a condensate - a macroscopically occupied single quantum state - which flows without resistance

In Simple Term

Crowd makes it hard to move.

Imagine if a person lifts you up and you surf over the crowd

Animation of Cooper pairs:

The Advantage….

Generators wound with superconductors could generate the same amount of electricity with smaller equipment and less energy.

Once the electricity was generated, it could be distributed through superconducting wires.

Energy could be stored in superconducting coils for long periods of time without significant loss.

The key Scientific terms….

The superconducting state is defined by three very important factors: critical temperature (Tc), critical field (Hc), and critical current density (Jc). Each of these parameters is very dependant on the other two properties present• critical temperature (T ) The highest temperature at which

superconductivity occurs in a material. Below this transition temperature T the resistivity of the material is equal to zero.

• critical magnetic field (Hc ) Above this value of an externally applied magnetic field a superconductor becomes nonsuperconducting

• critical current density (Jc) The maximum value of electrical current per unit of cross-sectional area that a superconductor can carry without resistance.

The Science Becoming

Reality

Emerging Applications

power transmission superconducting magnets in generators energy storage devices particle accelerators levitated vehicle transportation rotating machinery magnetic separators

Swiss Collider uses superconductivity

Cable – transmits 3 to 5 times more energy than copper wire

Source: Southwire

Transformer- 2 times overload capacity without insulation damage and environmentally

friendly due to lack of oil used in operation.

Source: Waukesha Electric Systems

HTS Motor – requires half the space of copper based motors

Source: Rockwell

SMES (Superconducting Magnetic Energy

Storage)

Source: American Superconductor

Forecasted Market Penetration Curves

Source: Analysis of Markets and Future Prices for High Temperature Superconductors

This is why Search for Absolute Zero is key

Superconductivity is in your future