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
Is it possible to see your whole body in a flat, planar mirror that is LESS THAN half your height if the mirror is at an angle? (i.e. not parallel to your body)

VELOCITY- TIME GRAPH: The graphs which represents the variation of velocity of an object with respect to time is known as velocity- time graph.

Quantum Theory of Light: Wave theory failed to describe some new effects in 19th century. A German Physicist Max Plank gave theory about the nature of light. 1. Light is emi

Q.  Explain Rayleigh's criterion of just resolution of two spectral lines of equal intensities giving suitable intensity distribution carves. Show how the resolving power of a pla

1.A=the set of whole numbers less tan 4 ? 2.B=the set of prime numbers less than 19 ? 3.C=the set of first three days of week?

A toy car with a mass of 0.75 kg is pulled3.2 m across the floor with a constant force of 110 N. If 67 J of work is done, what is the upward angle of the force?

Hexane is throttled from 18.15 bar, 507.6 K to 0.1 bar.  Determine the temperature at the exit and the entropy generation. Steam is cooled under constant pressure from 400 o C,

In a vacuum tube, electrons accelerate from the cathode element to the plate element, which is maintained at a positive potential with respect to the cathode. If the plate voltage

Planck constant; h: The fundamental constant equivalent to the ratio of the energy of a quantum of energy to its frequency. It refer to the quantum of action. This contains th

why is the colour of sky blue