Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets. In physics, several different types of magnetism are distinguished. Ferromagnetism (including ferrimagnetism) is the strongest type; it is the only type that creates forces strong enough to be felt, and is responsible for the common phenomena of magnetism encountered in everyday life. Other substances respond weakly to magnetic fields with two other types of magnetism, paramagnetism and diamagnetism, but the forces are so weak that they can only be detected by sensitive instruments in a laboratory. An everyday example of ferromagnetism is a refrigerator magnet used to hold notes on a refrigerator door. The attraction between a magnet and ferromagnetic material is "the quality of magnetism first apparent to the ancient world, and to us today".

Permanent magnets (materials that can be magnetized by an external magnetic field and remain magnetized after the external field is removed) are either ferromagnetic or ferrimagnetic, as are other materials that are noticeably attracted to them. Only a few substances are ferromagnetic; the common ones are iron, nickel, cobalt and most of their alloys, some compounds of rare earth metals, and a few naturally-occurring minerals such as lodestone.

Walter H. G. Lewin (born January 29, 1936), PhD, is a Dutch American astrophysicist and professor emeritus of physics at the Massachusetts Institute of Technology (MIT).

He earned his Ph.D. degree in nuclear physics in 1965 at the Delft University of Technology in the Netherlands.

Walter Lewin went to MIT in January 1966 as a post-doctoral associate, and became an assistant professor later that year. He joined an X-ray astronomy group at MIT and conducted all-sky balloon surveys with George W. Clark. Through the late seventies, there were about twenty successful balloon flights. These balloon surveys led to the discovery of five new X-ray sources, which doubled the number known at the time. Furthermore, some of these X-ray sources were found to be varying, and some were X-ray flares. The rockets used by other researchers could not have discovered that the X-ray sources varied because they were only in the air for a few minutes, whereas the balloons could be in the air for many hours. The surveys also resulted in the discovery of GX 1+4, which was the first slowly rotating X-ray pulsar found.

Andrey Igorevich Melnichenko (Russian: Андрей Игоревич Мельниченко, Belarusian: Андрэй Мельнічэнка, born on March 8, 1972 in Gomel, Belarus) is a Russian businessman and billionaire.

With a personal wealth of $10.8bn, in 2012 he ranked 81st in the Forbes World’s billionaires list (in Russia - #11).

Graduated from Boarding School of the Specialized Education and Research Centre under the auspices of the Lomonosov Moscow State University formerly called the Boarding School at Kolmogorov Physics-and-Mathematics School #18. [1]

Upon graduation was admitted into the School of Physics at Moscow State University, later transferred to and graduated from the Plekhanov Russian University of Economics.

1993: co-founded the MDM Bank which grew to become one of Russia’s largest private banks within ten years;

1993 - 1997 chaired the Management Board of MDM Bank, and during 2001 to 2005 chaired the Board of Directors.

1997: graduated from the Plekhanov Russian University of Economics as Finance and Credit major;
- bought out MDM Bank shares from his partners and became the sole shareholder of the Bank;
2000-2001: co-founded the MDM Group comprising industrial assets including Siberian Coal Energy Company (“SUEK”) and Mineral and Chemical Company “EuroChem”;
- became one of the founders of Pipe and Metallurgic Company TMK, Russia’s largest manufacturer and exporter of steel pipes. In 2004, sold his share in the transaction related to public placement of the company’s stock. with the London Stock Exchange;
2001—2004: MDM Group President;
2004-2007: Phased sale of all personally owned shares of MDM Bank to his MDM Group partner Sergei Popov, focuses on development of industrial/mining assets.
In 2007, Melnichenko acquired a stake of about 7% in the German competitor K+S, a potash and fertilizer producer based in the German town of Kassel. In 2008, Melnichenko increased his stake in K+S to about 15%.