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
Why population inversion is essential to achieve in lasing action? a) Define zener breakdown. b) What is called nanomaterials?

As an electron passes close to the positive nucleus of atom, the electron is moved from its path as given in diagram. This results in deceleration of the electron. The loss in powe

An object with a mass of 5 kilograms is a distance of 5 meters above the surface of the earth.  If the acceleration because of gravity is 10 meters per second squared, the pote

How nikol prisim can use as polarizer and analyzer

a) Heat produced is directly proportional to the square of the current passing by a conductor. b) This effect is produced because of collision of free electrons with positive io

Compare and contrast the pattern which is seen with two coherently illuminated narrow slits in Young's experiment with that seen for a coherently illuminated one slit producing dif

The heating elements of electric irons are made of (A) Copper.        (B) Nichrome. (C) Constantan. (D) Aluminium. Ans: The heating components of electric irons ar

UNIT AND DIMENSION OF DISPLACEMENT.  The S1-unit of displacement is metre (m).  The dimension of displacement is [L] or [M o LT o ]

Question: What sources electromagnetic radiation (a.k.a. light a.k.a. electromagnetic waves)? select the one BEST answer. Answer: Note the significant distinction betwe

Inertia with a spade Scoop up a spadeful of dry earth. Now pitch the earth away from you. View that when the spade stops the earth flies on due to inertia.