[Physics Class Notes] on Magnetization Magnetic Intensity Pdf for Exam

We have all played with magnets when we were young and we even remember it as well. Some of us even play with them now But what makes them ‘magnetic’? Have we ever thought why don’t all the materials and substances possess a magnetic field? Have we ever just wondered about it? In this chapter we are going to cover the topics which are magnetization and magnetic intensity.

As we know that the magnetization generally results from a moment which is said to be the magnetic moment. The motion which is of electrons that is in the atoms is what induces this. The net magnetization which we already know as a result from the response that is of a material to the external magnetic field. We can also recall here that it also takes into consideration any unbalanced magnetic dipole moment that is inherent in the material due to the motion of its electrons as we have mentioned earlier.

Magnetization

Magnetization is a term which is also termed as magnetic polarization which is said to be  a vector quantity that gives the measure of the density of permanent or we can say induced dipole moment in a given magnetic material. As we all already know that magnetization generally results from the magnetic moment, that is which results from the motion of electrons in the atoms or we can say that the spin of nuclei or the electrons. The net magnetization generally is said to result from the response of a material to the external magnetic field that is together with any unbalanced magnetic dipole moment that usually is inherent in the material due to the motion which is in its electrons as mentioned earlier. The concept of magnetization generally helps us in classifying the materials on the basis of their magnetic property. In this section we are going to  learn more about magnetization and the concept which is of magnetic intensity.

The Measurements which are of magnetic properties which have been used to characterize a wide range of systems from oxygen and metallic alloys and the solid state materials as well as the coordination complexes containing metals. Most organic and main groups are elements that are compounds which have all the electrons that are paired and these are said to be the diamagnetic molecules with very small magnetic moments. All of the metals that are transitioned have at least one state which is of  oxidation with an incomplete d subshell. 

The measurement which is of Magnetic is particularly for the first row transition elements which give the information about the number of unpaired electrons. That is the number of electrons which are unpaired that generally provides information about the oxidation state and along with that the electron configuration as well. The determination of the magnetic properties which are of the second and third row elements or the transition elements is more complex. The magnetic moment which we already know is calculated from the magnetic susceptibility that is since the magnetic moment is not measured directly we do it this way. There are several ways to express the degree to which a material acquires a magnetic moment which is in a field. 

Magnetic Intensity

The Magnetic behaviour that is of a magnet is said to be characterized by the alignment of the atoms which are inside a substance. When a substance which is ferromagnetic is brought under the application that is of a strong external magnetic field which is  then they experience a torque that is wherein the substance which aligns themselves in the direction of the magnetic field applied and hence gets strongly magnetized in the direction of the field or we can say the magnetic field.

All the substances which we have seen possess magnetic properties and the most general definition that is of magnetism defines it as a particular form which is of interactions originating which is in between moving electrically charged particles.

• The Magnetic interaction relates spatially separate objects to material and it is transmitted by means of fields which are magnetic about which we have already studied .This magnetic field which we know is important characteristics of the EM form of matter.

• We already know that the source which is of the magnetic field is a moving electric charge that is  an electric current. On the scale of an atom there are two types of macroscopic current which are associated with electrons.
  (a) the current which is orbital is which the electron in an atom moves about the nucleus that is in closed paths which is constituting electric currents loops
  (b) the current which generally spins relates to the internal degrees of freedom of the motion of electrons and this can only be understood through quantum mechanics.

• The electrons which are Like electrons in an atom and their  atomic nucleus may also have magnetic properties like magnetic moment but we note that it is fairly smaller than that of electrons then only.

• The moment which is Magnet denoted by  m is nothing but the quantitative measure of the magnetism of a particle.

• For an elementary loop which is closed with a current denoted by  i in it and the magnitude denoted by modulus |m| of a magnetic moment vector equals the current times the loop area S that is we can say that
  |m|=iS and direction of m can be determined using the right hand rule.

• All the micro structural which is of the elements of matter electrons and the protons and neutrons are elementary which generally carriers of magnetic moment and combination of these can be principal sources of magnetism

• Thus we can say that the magnetic properties are inherent to all the substances that is they are all magnets

An external magnetic field which we already know has an influence on these atomic orbital and spin currents and two effects of basic of an external field are observed

(i) the first is said to be a diamagnetic effect which is a consequence of Faraday’s law that is of induction. According to the Lenz law we can say that a magnetic field always sets up an induced current with its magnetic field direction opposite to a field or the initial field .Therefore the diamagnetic moment generally created by the external field is always said to be negatively related to this field.

Earth’s Magnetic Field

Earth’s magnetic field is the natural magnetic field that surrounds our planet. It is also known as the geomagnetic field. The earth’s magnetic field extends millions of kilometers into outer space and seems likely to be a bar magnet. The earth’s south magnetic pole is close to the North Pole. The magnetic north pole is in the South Pole, Antarctica. A compass magnet’s north pole points north as the magnetic property of the north and south poles attracting acts on earth and the compass.The Earth’s magnetic field spreads largely far and wide but is very ineffective in terms of field power. Earth’s natural Magnetism is generated by convection currents of molten iron and nickel in the planet’s core.

These currents hold streams of charged particles and cause magnetic fields and this magnetic field deflects ionizing charged particles coming from the sun which are also known as solar wind and control them from entering the atmosphere. Without this magnetic shield, the solar wind could have slowly eliminated the complete atmosphere stopping life on earth from existing. Mars, for example, does not have a strong atmosphere, and that’s why life can not sustain itself because it does not have a magnetic field covering and shielding it.

The earth’s magnetic poles are not geographically aligned to the actual north and south poles. The magnetic south pole is in Canada while the magnetic north pole lies in Antarctica. The magnetic poles are inclined by about 10 degrees to the earth’s original rotational axis.

Components of Earth’s Magnetic Field

The 3 components that are responsible for the magnitude and direction of the earth’s magnetic field-

• Magnetic declination- Magnetic declination is described as the angle between the true north and the actual magnetic north. On the horizontal plane, the true north is never at a steady position and keeps changing, relying upon the position on the earth’s surface and time.

• The magnetic inclination or the angle of dip- The magnetic inclination is also called the angle of dip. It is the angle created by the horizontal plane on the earth’s surface. At the magnetic equator, the angle of dip is always 0° and at the magnetic poles, the angle of dip is always 90°.