2. Aim
1
Displaying the hysteresis loop of a ferromagnetic material on the screen of
oscilloscope
2
Plot relation between dissipated energy on x-axis and the area of hysteresis
loop on y-axis
3
Plot relation between dissipated energy on x-axis and remnant magnetization
on y-axis
4 Plot relation between dissipated energy on x-axis and coercive field on y-axis
7. - The most important question, what happens by applying external magnetic
field on orbiting electron ?, whenan electron with magnetic dipole is placed
into external magnetic field, this magnetic field creates a torque unify the
direction of to its direction or it acts to orient it with that field
- We all know that the electron rotates around the nucleus and around itself
and this creates a magnetic dipole moment
- Now, since all materials contains electrons, so why most substances are not
magnetic ?, in most substances the magnetic dipole of one electron is
canceled by another electron orbiting in opposite direction, so we can
conclude that for most materials is zero or very small which makes it tends
to be zero
8. 02
- It is a region within magnetic material in which
magnetization is in a uniform direction, which means
large amount of magnetic moments are aligned
naturally in same direction
- In other words, the magnetic domains are tiny
magnets which need applying external magnetic field
to induce them to get aligned in same direction
- Domains only exists in ferromagnetic materials
- The process of using magnetic field to magnetize
another object is called induction, one once the object
has been induced, it produces its own magnetic field
because all domains are aligned in same direction
Magnetic
Domains
9. 03
2- Paramagnetic Materials: they are materials
which have some unpaired electrons and due to
these unpaired electrons, the net does not
equal zero, hence, by applying external magnetic
field, the paramagnetic materials are feebly
magnetized in the direction of the field
3- Ferromagnetic Materials: they are materials which tends to be strongly magnetized
by applying external field, these materials have its own at which most of them are
aligned in same direction, so with induction, all of them will be aligned in the same
direction , an example of these materials are: iron, cobalt,……etc
Classification of materials
1- Diamagnetic Materials: they
are materials at which there are
no dipoles due to pairing
between electrons, by applying
external magnetic field, dipoles
are induced in opposite direction
10. 04 Formation Of Loop
- If we have ferromagnetic material, and we start applying external magnetic field on
it, we will get this result:
- Once we apply external
field, the domains will be
aligned in same direction and
if we increase the field, they
will be aligned till point of
saturation
11. - If we remove this external field, because of retentivity of ferromagnetic
materials, most of domains will stay aligned and few of them will not stay
aligned
- If we apply external field but
in the opposite direction, so
domains will be aligned
gradually in the direction of
the field
12. - We will increase the field till half of domains are aligned in the direction
of the field while the other half of domains not yet, so both halves cancel
each other
- If we increase the field,
more domains will be
aligned in the direction of
the field till all of them will
be aligned in the direction
of the field and if we
increase it more we will
reach saturation
13. - If we remove the field, because of retentivity of ferromagnetic materials, most
of domains will stay aligned and few of them will not
- By applying the field in the other direction, the domains will be aligned
gradually till half of them will be aligned and the other half of domains not
yet, so both of halves will cancel each other, and if we increase the field
more, all of domains will be aligned in the direction of the field, and increase
the field more, we will reach a saturation
14. - It is important to mention that changing the field needs energy and
sure there is loss of energy and we call this energy “ Dissipated
Energy “ and this energy is lost in form of heat
- In our experiment the process of changing the direction and
intensity of the magnetic field happens by using alternating current
because it is variable in direction and intensity, so it will also
generate variable magnetic field in direction and intensity
