MAGNETIC MATERIALS – DIPOLE MOMENT
Materials which has got the ultimate capacity of attracting pieces of Iron, nickel, cobalt , dyasporium when they are subjected to external field can be noticed as an important property of magnetic materials. Magnetic materials will not exist as a monopole they always exist as a dipole, because even if we break the magnetic material into pieces the tiny pieces of magnet will also behave as a dipole. Actually the dipole in a magnet is formed due to two reasons
1. Orbital Motion 2. Spin motion of electron
We know that electron revolves round the nucleus in definite circular orbits and with consistent energy levels. If the path of this electrons is treated as circular current loop it produces some electric force, due to the generation of this electrical force the size of the nucleus in the material gets distorted, as a result of this the shifting of +ve and –ve charges will take place resulting in the formation of dipole. The moment of such dipole is known as orbital magnetic dipole moment. Generally dipole moment can be defined as the product of pole strength and geometrical length of the bar magnet . The unit of pole strength is Ampere-metre. In addition to the electron revolving round the nucleus in definite circular orbits it spins on its own axis, as a result of which the displacement of positive and negative charges takes place, the moment of such dipoles is known as the spin magnetic dipole moment .
The Essay on The Information Age Is Upon Us The Raw Materials Are
The information age is upon us. The raw materials are ones and zeros. The technology used to transport the ones and zeros provides numerous opportunities for entrepreneurs, scientists, and engineers. Telecommunications is dynamically changing the way we work, learn, communicate, and view society. At no other time in history have so many people been given the ability to exchange ideas, sell their ...
There is another type of magnetic moment called Nuclear magnetic moment where the absolute moment of nucles and electrons will take place.
Depending on the alignment of atoms and their response to the external magnetic field at a given point of time magnetic materials can be broadly classified into 5 types.
1. Diamagnetic materials.
2. Ferromagnetic materials.
3. Paramagnetic materials.
4. Antiferromagnetic materials.
5. Ferrimagnetic materials.
1. Diamagnetic materials :- There are certain class of materials which cannot allow the magnetic lines of force to penetrate into the material there may be different reasons one is due to the negative susceptibility of the material i.e incapability of the material to allow magnetic lines of force, the another reason is diamagnetic materials themselves contains a small perpetual currents called persistent currents, this persistent currents inside the material will generate small magnetic field opposite to the direction of the external magnetic field as a result of this magnetic lines of force will draw away from the material. Hence diamagnetic materials are not much used in our daily life because of its negative susceptibility. The alignment of atoms in the diamagnetic materials is as shown below.
2. Ferromagnetic materials :- Materials which are strongly attracted to the external magnetic field are called ferromagnetic materials, ferromagnetic materials show strong magnetisation due to the presence of a) spontaneous magnetisation b) Hysterisis
Spontaneous magnetisation is a property where the magnetisation will be present in the material even in the absence of the external magnetic field.
In general a ferromagnetic material is divided into small regions called domains, domains are the regions where the spins of electrons are aligned in same direction, but when we consider the total volume of the material the net magnetisation of material is zero because in each domain of the ferromagnetic material some set of spins will be in anticlock and remaining will be in clockwise direction. When we apply the external magnetic field to this ferromagnetic material they react strongly to the field, because ferromagnetic materials strongly allow the magnetic lines of force into the material thereby making the material strongly magnetised hence their permeability is far greater than 1. But the magnetisation of ferromagnetic material takes place in two ways
The Essay on Magnetic Field Angular Momentum Direction
Some materials have a feature known as ferromagnetism. The prefix 'ferro' refers to Iron, which is one such material. Ferromagnetic materials have the ability to 'remember' the magnetic fields they have been subjected to. An atom consists of a number of negatively charged electrons, orbiting around a positively charged nucleus. These electrons also possess a quantity known as spin, which is ...
1. Easy magnetisation 2. Hard magnetisation
2.
Easy magnetisation means if sufficient small magnetic field is applied to a magnetise a material it is termed as easy magnetisation, on the other hand if bulk magnetic field is applied to magnetise a material it is termed as hard magnetisation. A ferromagnetic material has an important property called curie temperature where the ferromagnetic material suddenly transits to paramagnetic material. Above this curie temperature it behaves as paramagnetic material and below this temperature they behave as ferromagnetic material.
Paramagnetic materials :- The materials which are magnetised in presence of external magnetic field are called paramagnetic materials because the permeability of paramagnetic materials is greater than 1 they become magnetised when we apply external field, but lesser magnetisation when compared to ferromagnetic material.
In the absence of external magnetic field the net magnetisation is zero because all the spins of electrons are arranged in random direction. But as soon as magnetic field is applied they tried to orient into the direction of magnetic field.
Antiferromagnetic materials :-
In the case of antiferromagnetic material the alternate spins of electrons are arranged in parallel direction whereas the neighbouring spins of electrons will be antiparallel to each other as a result of this the resultant magnetisation of this material will be zero. Important property of antiferromagnetic material is neel temperature where the material will be converted from antiferro to paramagnetic material form. Above the neel temperature it behaves as paramagnetic material and below the neel it behaves as antiferro phase.
The Essay on Magnetic Fields And Magnetic Force
1. What happens to the distribution of magnetic flux lines when the iron ring was placed in between the U-magnets? The distribution of magnetic flux lines when the iron ring is placed in between the magnets, the iron ring is included in the distribution of flux lines. Instead of connecting to the other pole, the ring affects its distribution and some of it is attracted to the iron ring. 2. How ...
