The Materials, Properties, and Theory of Superconductivity Essay

The magnetic field rotates 180 degrees when the battery slider moves from one side of the battery to the other.

The figure depicts the excitation of an electron into the conduction band thus leaving a hole in the valence band. An electron-hole pair is called an exciton, and the natural physical separation between them is called the excitonic Bohr radius and is characteristic of each material. Thus when a semiconducting material approaches a size nearing its Bohr excitonic radius, the exciton is said to be confined within the particle and is called quantum

In order to observe quantum mechanical effects in a gas, we have to reduce the temperature drastically. Roughly, we can calculate this temperature by demanding that the thermal deBroglie wavelength has to become equal to the mean particle distance $\lambda\approx10\,\,\textrm{nm}$ $\Rightarrow T=\frac{\hbar^{2}}{3mk_{\text{B}}\left(10\,\,\textrm{nm}\right)^{2}}\approx0.002\,\,\textrm{K}$. % }, hence, as a matter of fact, the atomic BECs are the coldest objects existing in labs. BEC's creation became only possible after the development of appropriate experimental techniques needed to reach the necessary ultra-low temperatures. Mainly, we can divide the cooling procedure of atoms into main steps, \textbf{First}:- the method of laser cooling is applied to the gas loaded into a magneto-optical trap, this method was rewarded with the Nobel Prize in Physics for 1997 \cite{RevModPhys.70.685,RevModPhys.70.707,RevModPhys.70.721}, this method makes it possible to create a moderately cool state, at temperature $\sim100\,\,\mu\textrm{K}$. \textbf{Second}:- this step undergoes forced evaporative cooling, losing $\sim90\%$ of atoms, and the remaining atomic cloud spontaneously forms the

Dr. Shirley Jackson is the president of Rensselaer Polytechnic Institute, but she didn’t get there easily. From 1964-68 she was a scholar at MIT (Massachusetts Institute of Technology), after graduating in 1964 as valedictorian of her class. Here, she earned her bachelors degree after writing her thesis on solid-state physics. She also got her Ph.D. in ’73 on elementary particles, becoming the first African American female to receive a doctorate in theoretical solid state.

There are 3 types of metals for electricity conducting: metallic conductor, semiconductor, and superconductor. Metallic conductors allow the free flow of ions and electrons through a sample; and its conductivity decreases as the temperature increases.

Copper (Chemical symbol Cu, Atomic number 29), is one of the best electrical conductors in all metals, has influenced the use of telecommunications throughout the world. We rely on copper for a lot of things - power, heating, lighting, transport, communication, and even coinage. The wide application of copper in our daily lives has made our homes, schools and businesses pleasant, decorative and efficient but also has created negative impacts in our environment.

Copper is an inexpensive metal that occurs in abundance in communities where copper mining has occurred, such as Queenstown, Tasmania. Copper resists corrosion and an effective conductor of heat and electricity.

When metal atoms pack together in a specific and orderly fashion metals such as gold, silver, and copper are produced. Each metallic atom gave up its valence electron to form a common pool of electrons in the entire structure. The freedom of valence electrons to

and a much lower superconducting transition temperature TC relative to the β phase: ca. 0.015 K vs. 1–4 K; mixing the two phases allows obtaining intermediate TC values. The TC value can also be raised by alloying tungsten with another metal . Such tungsten alloys are sometimes used in low-temperature superconducting circuits.

Our sun is halfway through its life cycle and based on the studies of the stars, when it reaches the last stages of its life it will go supernova destroying Earth, but that won’t happen in about 5 billion years.

* Lim Peng Chew, Lim Ching Chai, Nexus Bestari Physics, Sasbadi Sdn. Bhd. , 2013, Pg 18,19

Copper has many chemical properties that make it unique. The Atomic number of copper is 29. An Atomic number is a measure of the amount of protons in the nucleus of an atom. Protons are sub-atomic particles, which have a positive charge. The Atomic mass of copper is 63.546. The Atomic mass is a measure of how many neutrons and protons are in an atom. Neutrons are

In the Quantum Free Electron Theory the electrons are considered as waves, so the electrons will have much similar behaviour to waves. The temperature is related to the heat capacitance. So each element will have different heat capacitance.

In the early 1900's a duch physicist by the name of Heike Kammerlingh Onnes (pictured above), discovered superconductivity. Before his discovery, Onnes had spent most of his scientific career studying extreme cold. The first step he took toward superconductivity was on July 10, 1908 when he liquified helium and cooled it to an astonishing 4 K, which is roughly the temperature of the background radiation in open space. Using this liquid helium, Onnes began experimenting with other materials and their properties when subjected to intense cold. In 1911, he began his research on the electrical properties of these same materials. It was known to Onnes that as materials, particularly metals, cooled, they exhibited less and less resistance. Bringing a mercury wire to as close to absolute zero as possible, Onnes observed that as the temperature dropped, so to did the resistance, until 4.2 K was reached. There resistance vanished and current flowed through the wire unhindered. Below is an approximate graph displaying resistance as a function of temperature for the experiment Onnes conducted with mercury:

We have now discussed the two extremes in electronic materials; a conductor, and an insulator we will now move to a material that lies in between these two, a semiconductor. The