[Physics Class Notes] on Diamagnetic Elements Pdf for Exam

Magnetism is the resultant product of electrons’ spin motion and their interaction with one another. Different objects respond differently to different objects. So, we can describe the various magnetic materials by describing their responsiveness to magnetism. When you study the behavior of objects, you will find that most of the objects are like magnets, and in other words, we can say that all the matter is magnetic. Their magnetism may be different. Some matters are more magnetic, and some are less magnetic. Well, you will be surprised by what makes the difference between the magnetism of different matters. We have already discussed that the motion and interaction of electrons are responsible for the magnetism property of any object. The level of electron interaction makes such variation in magnetism. Some materials have no collective interaction while other materials may have intense atomic electron moments and interaction.

 

Discovery of Diamagnetism

The special property of diamagnetism came to be known in the late 1700s, by the discoverer Anton Brugmans in the element Bismuth, which showed repelling properties to a magnetic field when brought near to it. However, it was the great physicist Michael Faraday, who first concluded the presence of diamagnetism. He also concluded that all materials exhibit this property to some extent. He showed that all materials respond to magnetic fields in one or another way (either attracting or repelling). At the suggestion of English Polymath and fellow scientist William Whewell, Faraday termed the phenomenon to be “Diamagnetic” which later changed to “diamagnetism”. 

In Chemistry, these magnetic properties are assigned to the electron based on their pairing with each other and spin at the subatomic level. At these levels we understand diamagnetism to be retrained electrons being settled in their orbitals, effectively producing zero resistance and acting like loops of current. However, paramagnetism and ferromagnetism arise once they gain energy and lose their effective position in assigned orbitals. The electrons may then start to become unpaired and show ferromagnetic or paramagnetic properties in a magnetic field.  As a thumb rule, if the electrons are paired, the material is said to be Diamagnetic; if the electrons are unpaired, the material is called to be paramagnetic.

 

Magnetic Materials: Classification

How objects respond to the external magnetic energy defines the magnetic property of objects. Here we will discuss the magnetism of solid substances, and classification can be done in three categories.

Diamagnetic: Diamagnetic Meaning

Generally, the Magnetic field of external substances attracts the materials, but some materials are prone to a magnetic attraction. Such materials or substances are called Diamagnetic. Examples of Diamagnetic fields are water, mercury, gold, copper, and bismuth.

Paramagnetic

Substances that are weakly attracted to magnetic materials are paramagnetic. Examples of paramagnetic materials are Lithium, Molybdenum, Magnesium.

Ferromagnetic

Materials that are strongly attracted to magnetic materials. Examples of ferromagnetism are Nickel, Iron, and Cobalt. 

 

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Diamagnetic (Magnetic Field)

Diamagnetic materials, for the most part, repulse from a magnet. These solids make an instigated attractive field toward a path inverse to a remotely applied attractive power and are repulsed by the applied attractive field. This wonder is the polar opposite conduct shown by paramagnetic materials. 

The orbital movement of electrons present on the molecules of Diamagnetic solids produces attractive fields as it makes little nuclear current circles. At the point when attractive outside power is applied to a material, these current circles will, in general, adjust to restrict the applied field. 

In Diamagnetic materials, there is no perpetual net attractive second per iota as all the electrons are combined. Because of the impact of an attractive outside power, Diamagnetic properties emerge from the realignment of the electron pathways. Most components in the occasional table like copper, silver, and gold, are Diamagnetic. Sebald Justinus Brugmans found diamagnets in the year 1778. Michael Faraday further showed that diamagnetism or attraction is a property of an issue, and each material or durable response needs be. 

 

Attractive Susceptibilities of Diamagnetic Materials  at 20°C 

Km is the relative penetrability which is only an amount that quantifies the proportion of the in-charge to the applied attractive field. 

Material

χm= Km-1 (x 10-5)

Carbon (graphite)

-1.6

Ammonia

-2.6

Silver

-2.6

Bismuth

-16.6

Carbon (diamond)

-2.1

Mercury

-2.9

Lead

-1.8

Water

-0.91

Copper

-1.0

Sodium chloride

-1.4

The gasses N2 and H2 are weakly Diamagnetic with susceptibilities of -0.0005 x 10-5 for N2 and -0.00021 x 10-5 for H2. The gasses N2 and H2 are weakly Diamagnetic with susceptibilities of -0.0005 x 10-5 for N2 and -0.00021 x 10-5 for H2.

 

What is Magnetic Susceptibility?

Susceptibility is a measure to extend to which material gets magnetic energy under the influence of an external magnetic object or field. In other words, we can use the term “magnetizability” for the susceptibility of magnetic material.

Polarization or magnetism is created when an object interacts with the magnetic field. Polarization may either augment or oppose the external field. Object’s active field is reduced because of the opposition of the applied magnetic field by the polarization. In this situation, the magnetic lines are dispersed because of polarization, and this effect is called Diamagnetic.

 

Magnetic Susceptibility of Diamagnetic Substance

Attractive materials might be named Diamagnetic, paramagnetic, or ferromagnetic based on their susceptibilities. Diamagnetic materials, for example, bismuth, when put in an attractive outer field, mostly remove the outside field from inside themselves and, whenever molded like a bar, line up at right edges to a nonuniform attractive field. Diamagnetic materials are portrayed by consistent, little unfavorable susceptibilities, just marginally influenced by chang
es in temperature.

 

Superconductivity

An unusual property arising out of diamagnetism, and only recently known, is the property of superconductivity. The phenomenon was first discovered by Dutch physicist Heike Kamerlingh Onnes, who demonstrated that when materials are cooled to an absolute zero, phase transition occurs accompanied by special magnetic properties, not known to exist otherwise. Unlike other materials, Diamagnetic substances, under special circumstances (specific temperature and pressure conditions) act like superconductors. They have a specific set of physicochemical properties such as zero electrical resistance, net zero magnetic flux fields, and phase transition with no latent heat. It then shows the characteristic Meissner Effect. It is the “idealization of perfect conductivity” in classical physics. An electric current that loops through such a superconducting material can continue to exist indefinitely (for an infinite time) even after the source of current is removed. These special properties conferred upon by diamagnetism make it a swiftly developing field of classical physics. 

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