Classes of magnetic materials: ferromagnetism, Physics

When you think of magnetic materials, you possibly think of nickel, iron or magnetite. Distinct to paramagnetic materials, the atomic moments in these materials show very strong interactions. These interactions are produced by electronic exchange force. They result in a parallel alignment of atomic moments. The exchange force is a quantum mechanical phenomenon due to the relative orientation of the spins of the two electrons. Ferromagnetic materials show parallel alignment of moments resultant in large net magnetization even in the lack of a magnetic field. The elements Ni, Fe, and Co and most of their alloys are typical ferromagnetic materials: Two distinct characteristics of ferromagnetic materials are there:

(A)       Spontaneous magnetization and

(B)        The existence of magnetic ordering temperature

SPONTANEOUS MAGNETIZATION

The spontaneous magnetization is that exists inside a uniformly magnetized microscopic volume in the absence of field. The magnitude of this magnetization, at 0k, is dependent on the spin magnetic moments of electrons. An interrelated term is the saturation magnetization which we can calculate in the laboratory. The situation magnetization is the maximum induced magnetic moment that can be obtained in a magnetic field. Beyond this field no more increase in magnetization takes place.

CURIE TEMPERATURE

Electronic exchange forces in ferromagnetism are very large. Thermal energy ultimately overcomes the exchange and generates a randomizing effect. This takes place at a particular temperature known as Curie temperature. Below the curve temperature, the ferromagnetic is ordered and above it disordered. The saturation magnetization moves to zero at the Curie temperature. A typical plot of magnetization versus temperature for magnetic.

HYSTERESIS: In additional to the Curie temperature and saturation magnetization. Ferro magnets can keep a memory of an applied field also once it is removed. This behaviour is called hysteresis a plot of the variation of magnetization with magnetic field is a hysteresis loop. Another hysteresis property is the coercively of reminisce. This is the reverse field which when applied and then removed, reduces the saturation reminisce to zero. It is always large then the coercive force.

Posted Date: 7/7/2012 7:56:43 AM | Location : United States







Related Discussions:- Classes of magnetic materials: ferromagnetism, Assignment Help, Ask Question on Classes of magnetic materials: ferromagnetism, Get Answer, Expert's Help, Classes of magnetic materials: ferromagnetism Discussions

Write discussion on Classes of magnetic materials: ferromagnetism
Your posts are moderated
Related Questions
Q. Illustrate what is balanced field takeoff? Answer:- A balanced field with admiration to aircraft takeoff performance refers to the minimum length of runway that will pe

Power: The rate of doing work is called power, and it is defined as the work done in unit time.  As a formula, this would be: power = work done/time Taken  Power is exp


what the main defination of current? Electrical current is a measure of the amount of electrical charge transferred per unit time. It represents the flow of electrons through a

Question: A wire loop as well as a bar magnet lie in one and the same horizontal plane. The bar magnet is exterior of the loop. The bar magnet is rotating at a constant rate co

An object that is 24 cm from a convex  lens produces a real image that is 13 cm from the lens. What is the focal length of the lens?

Q. What are polar molecules? Give an example. i) A polar molecule is one in that the centre of gravity of the positive charges is separated from the centre of gravity of the ne

How does the distance between fringes in Young's double slit experiment change. a) If the colour of the light is changed from red to blue? b) If the slit separation is incre

A steam turbine takes in saturated steam at 300 C and outputs steam at 4 bar. If the efficiency of the turbine is 65%, calculate: a. The final composition (vapor vs. Liquid) of

(1)          Melting point : 936 0 C (2)          Atomic number : 32 (3)          Energy gap : 0.6ev (4)          It is a gray metallic looking mat