January 21, 2016 (Revised and re-posted on April 23, 2020)
In my first report published earlier (Jan 8, 2016), I reported that the history of the magnetic materials and the field of magnetism date back to ancient times – well before the stone and pre-stone ages, and tried to provide a relationship between magnetism and-bio medicine. In this report, I will elaborate on how these magnetic materials were perceived in old ages and what led them to become most important materials in the modern era.
Interestingly, the magnetic history and the history of science began at the same time. The curiosity in magnetic materials is prompted by the ability of the invisible and remote-control nature of magnet to attract or dispel materials from a distance. To understand more about the invisible magnetic energy or force, we need to have either two pieces of permanent magnets, or one permanent magnet and other pieces of magnetic materials such as Fe, Co, Ni, etc., or even Loadstones – weak magnetic materials.
Loadstones are widely popular and abundantly available rocks in the earth and are rich in magnetite -also known as Fe3O4. These rocks are fascinating because they are still very good magnets, though they were magnetized by huge lightning strikes thousands of years ago.
While it would not be wrong to say that the application of magnets dates back to stone and pre-stone ages, to our knowledge, the initial application of magnet in the form of “Spoon, also named as a south pointer” by humans’ dates back to mid-11th century (1064 AD) in China. A century later, a European re-invented the magnet in the form of a compass. The discovery of the compass eventually helped Mr. Christopher Columbus discover America in the late 15th century (1492 AD). Between the periods of the 5th and 15th century, also known as the medieval age, many compared the magnet to the human soul because of its interesting movement, and also believed that the alignment of the compass along the north and south direction was due to the effect of the positioning of stars around the earth. After the medieval age, however, it was, Gilbert who investigated the phenomenon of magnetism systematically using scientific method in the early 17th century (1600 AD).
The investigation on magnetism and magnetic material continued and an important development in magnetism was made by Swiss Mathematician Daniel Bernoulli in late 18th century (1743 AD) who invented Horse Shoe magnet, that is still widely used in school text books around the globe.
By the 18th century, people already knew that magnets have two poles, one is north and the other south. By now, they also knew that electrons in metals have two charges, negative and positive.
A true relationship between magnets (magnetism) and electrons (electricity), was accidently discovered in the early 19th century (1820 AD) by Hans Christian Oerstan from Denmark. Immediately after that, Andrew-Marie Ampere and Dominic Francois Arago from Paris, demonstrated that a current carrying coil was equivalently a magnet.
It was Michael Faraday who discovered electromagnetic induction in the early 19th century (1821 AD). He used a “still” magnet, a current carrying coil, and discs of mercury to demonstrate the principle of electric motor. Michael Faraday also discovered the interrelationship between magnetics and optics in the late 19th century (1845 AD). In the next report, you will learn more about magnetic materials and magnetism, and their potential applications in health care industry.
To download the relevant text, click Ferromagnetic Alloys: Magnetoresistance, Microstructure, Magnetism, and Beyond (Review)