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What is Curie's Law?

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According to the Curie’s Law, the magnetization which is present in a paramagnetic material is said to be directly proportional to the applied field of magnetic. If the object which we have used is heated then the magnetization is viewed to be temperature which is inversely proportional. The law which we are discussing was discovered by the French physicist named Pierre Curie.


Most of the elements and along with some compounds which are paramagnetic in nature. Paramagnetism is exhibited by compounds which are containing palladium, iron, platinum, and the earth rare elements. In such compounds which are made up of atoms of these elements have some inner shell electrons that are incomplete. This causes their unpaired electron to spin like orbits and tops like satellites. This makes the atoms magnetic which tend to align with and strengthen an applied field of magnetic.


Magnetic effect of strongly paramagnetic substances decreases with temperature increase because of the dealignment produced by the greater random motion of the atomic magnets. Magnets exhibiting weak paramagnetism are independent of temperature which is found in many elements which are metallic in the solid state. For example, sodium and the other metal alkali. It is because an applied magnetic field affects the spin of some of the loosely bound conduction electrons. The susceptibility value that is a measure of the relative amount of induced magnetism for magnets that are paramagnetic materials is always positive and at room temperature. That is we can say is typically about 1/100,000 to 1/10,000 for the magnets which are weakly paramagnetic and about 1/10,000 to 1/100 for strongly paramagnetic magnets.


Curie's Law Formula 

Curie’s Law can be framed very easily into an equation.

That is - M = C x (B/T)

Wherein,

M is = Magnetism

B is = Magnetic field in Tesla

T is = absolute temperature in Kelvins

And C is = Curie constant


Curie Temperature

Paramagnetic materials such as platinum or aluminium sometimes are magnetized in a magnetic field and their magnetism becomes extinct when the field doesn’t exist. Ferromagnetic materials like iron and nickel that retain their properties of magnetic fields when the field is erased.


The temperature of Curie is the one at which ferromagnetic material turns to paramagnetic on heating. This kind of transition which we are observing over here is used in optical storage media for erasing and inserting the data which is new.


In a material which is paramagnetic the magnetization of the material is said to be directly proportional to an applied field of the magnet. However, if the material is heated then this proportionality is reduced basically for a fixed value of the magnetic field which is inversely proportional to T that is the temperature.

M = C.B/T


Paramagnetism and Diamagnetism 

The magnet which is paramagnetic in nature exhibits a kind of magnetism where several objects are attracted to them through an externally applied magnetic field. On the other hand, the materials which are diamagnetic are repelled by magnetic fields and develop an induced field of magnetic direction which is said to be opposite to that of the applied magnetic field.


These materials which we have discussed include most of the elements which are chemical elements and some compounds which have a magnetic permeability greater than or equal to 1. 


Magnetic Moment

The moment of a magnet which is induced by the applied field is linear to the weakness or the strength of the field. It is usually said that it needs a sensitive balance that is analytical to detect the different modern measurements and effect on the material which is paramagnetic. This is often conducted with a SQUID magnetometer.


Conclusion

The law of Curie and the temperature of Curie are important topics in IIT JEE. The few topics which are related to curie's law are the topics usually which fetch direct questions in the exam and so it becomes vital to master them. These topics like Curie's temperature and law include various formulae which fetch direct numerical questions. They are quite very easy and these topics don’t require much practice but it is very much important to clarify these concepts of curies.

FAQ (Frequently Asked Questions)

Q1. What is the Law of Curie for Paramagnetism?

Ans: According to Curie’s Law, in a paramagnetic substance magnetization of the material is inversely proportional to the temperature. This implies the more the temperature of the material or increase in paramagnetism then its magnetization decreases. 

Q2. What is Curie Temperature in Paramagnetic Material?

Ans: The temperature at which a transition occurs between the paramagnetic and the ferromagnetic phases occurs. Curie point is the temperature above which material which is of magnetic nature lose their ferromagnetic properties which are then replaced by paramagnetism.

Q3. Define Pauli Paramagnetism.

Ans: Pauli paramagnetism: For some metals, which are alkali and metals which are noble conductors of electrons are weakly interacting and they are weekly delocalized in space forming a gas fermi. These materials contribute to the magnetic response which comes from the interaction between the spins of electrons and the magnetic field known as Pauli paramagnetism.

Q4. Mention the Significance of Curie Temperature.

Ans: Above the point of Curie which is also called the Curie temperature, the magnetization which is spontaneous of the ferromagnetic material vanishes and it becomes paramagnetic, i.e/. It remains weakly magnetic. This occurs because the thermal energy becomes sufficient to overcome the internal force aligning of the material.