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
In the SI system of measure, what is the unit of capacitance? Ans: In the SI system of measure, farad is the unit of capacitance.

A 0.150-kg ball that is thrown at a velocity of 30.0 m/s hits a wall and bounces back in the opposite direction with a speed of 25.0 m/s. How much work was done by the ball?

Regard as two Styrofoam cups. Each one is on the end of its own neutral slender glass rod which serves as a handle. One of the cups has a fixed amount of positive charge consistent

What Is Normal Reaction ?How To Find It? Normal reaction is the force acting among two contact surfaces. Like, if you push a wall, you will feel an opposite force acting on yo

A rod follower AB is subjected to a vertical up and down movement while resting on a circular contour of radius 30cm of a cam.the cam moves to the right with a velocity of 5 cm/s a

Instantaneous velocity and speed are explained at a given or particular instant and are shown by  ,


The mass of a string is 4.20 x 10 -3 kg, and it is stretched so the tension in it is 135 N. A transverse wave traveling on this string has a frequency of 260 Hz and a wavelength o

REST: A body is said to be at rest if it does not alter its position with respect to its surroundings.

The structure of a simple d.c. motor and explain briefly how it works