Magnetization and Application of Ampere’s Law - Magnetic Susceptibility
Magnetization is the process of aligning the magnetic domains within a material, resulting in a net magnetization.
Ampere’s law relates the magnetic field around a closed loop to the electric current passing through the loop.
Magnetic susceptibility is a measure of how easily a material can be magnetized.
Magnetization
Magnetization is the process by which magnetic domains within a material align to create a net magnetic field.
It occurs when an external magnetic field is applied to the material.
The domains align along the direction of the external field, resulting in a net magnetization.
Different materials have different inherent magnetic properties, resulting in varying levels of magnetization.
Ampere’s Law
Ampere’s law relates the magnetic field around a closed loop to the electric current passing through the loop.
It states that the line integral of the magnetic field along a closed loop is equal to μ₀ times the enclosed current.
∮B·dl = μ₀I_enclosed
B: Magnetic field, dl: Differential length element, μ₀: Permeability of free space, I_enclosed: Enclosed current
Magnetic Susceptibility
Magnetic susceptibility is a measure of how easily a material can be magnetized in response to an external magnetic field.
It is defined as the ratio of the induced magnetization to the applied magnetic field intensity.
χ = M/H
χ: Magnetic susceptibility, M: Magnetization, H: Applied magnetic field intensity
Materials with positive susceptibility are attracted to a magnetic field, while those with negative susceptibility are repelled.
Magnetization and Application of Ampere’s Law - Magnetic Susceptibility
Slide 11
We can calculate the magnetic field inside and outside a long straight conductor using Ampere’s law.
If the conductor carries a steady current, the magnetic field lines form concentric circles around the conductor.
The magnitude of the magnetic field decreases as the distance from the conductor increases.
Slide 12
The direction of the magnetic field lines can be determined using the right-hand rule.
If the thumb of the right hand points in the direction of the current, the curled fingers indicate the direction of the magnetic field.
Inside the conductor, the magnetic field lines form clockwise circles, while outside the conductor they form counterclockwise circles.
Slide 13
The strength of the magnetic field inside a long straight conductor is given by:
B = (μ₀ * I) / (2π * r)
B: Magnetic field strength, μ₀: Permeability of free space, I: Current, r: Distance from the conductor
Slide 14
The strength of the magnetic field outside a long straight conductor is given by:
B = (μ₀ * I) / (2π * R)
B: Magnetic field strength, μ₀: Permeability of free space, I: Current, R: Distance from the conductor
Slide 15
In a solenoid, a coil of wire is wound on a cylindrical core.
The magnetic field inside a solenoid is uniform and passes through the center of the coil.
The strength of the magnetic field inside a solenoid is given by:
B = μ₀ * n * I
B: Magnetic field strength, μ₀: Permeability of free space, n: Number of turns per unit length, I: Current
Slide 16
Magnetic susceptibility is a dimensionless quantity that measures the extent to which a material can be magnetized.
It is defined as the ratio of the magnetization of a material to the applied magnetic field intensity.
Magnetic susceptibility can be positive, negative, or zero.
Materials with positive susceptibility are called paramagnetic.
Materials with negative susceptibility are called diamagnetic.
Materials with zero susceptibility are called non-magnetic.
Slide 17
Paramagnetic materials have unpaired electrons, which can align their magnetic moments with an external field.
This alignment leads to an increase in the magnetic moment within the material, resulting in positive magnetization.
Examples of paramagnetic materials include aluminum, platinum, and oxygen.
Slide 18
Diamagnetic materials have all their electrons paired, resulting in zero net magnetic moment.
These materials have a negative susceptibility, meaning they are repelled by an external magnetic field.
Examples of diamagnetic materials include water, gold, and copper.
Slide 19
Non-magnetic materials have no unpaired electrons and cannot be magnetized.
These materials have zero susceptibility as they show no response to an external magnetic field.
Examples of non-magnetic materials include wood, plastic, and glass.
Slide 20
The magnetic susceptibility of a material depends on various factors such as temperature and composition.
In paramagnetic materials, the susceptibility decreases with increasing temperature, while in diamagnetic materials, it remains constant.
The susceptibility of a material can also be modified by doping or applying external magnetic fields.
Slide 21
The susceptibility of a material can be determined experimentally.
It is measured by comparing the magnetization of the material with and without an applied magnetic field.
The ratio of the two magnetizations gives the magnetic susceptibility.
Slide 22
The susceptibility of a material can be described in terms of its magnetic permeability, which is a measure of the material’s ability to support the formation of a magnetic field.
The relationship between susceptibility (χ) and permeability (μ) is given by:
μ = μ₀(1 + χ)
μ₀: Permeability of free space
Slide 23
Magnetic susceptibility is an important property in the study of magnetic materials and their applications.
It helps in understanding the behavior of materials in the presence of magnetic fields.
Magnetic susceptibility is used in various fields like materials science, geophysics, and medical imaging.
Slide 24
In the case of materials with positive susceptibility (paramagnetic), the magnetic moments align with the external field, leading to a stronger magnetic field within the material.
This property is utilized in applications such as magnetic resonance imaging (MRI), particle accelerators, and magnetic separation techniques.
Slide 25
Negative susceptibility (diamagnetic) materials are repelled by magnetic fields and do not retain magnetization once the external field is removed.
Diamagnetic materials find applications in fields such as magnetic levitation, superconductors, and magnetic shielding.
Slide 26
Intermediate values of magnetic susceptibility are observed in materials known as ferrimagnetic and ferromagnetic.
These materials have spontaneous magnetization even in the absence of an external field.
They find applications in transformers, motors, magnetic memories, and magnetic storage devices.
Slide 27
The magnetic susceptibility of a material is temperature-dependent.
In paramagnetic materials, as the temperature increases, the thermal energy disrupts the alignment of magnetic moments, resulting in a decrease in susceptibility.
Diamagnetic materials, being independent of atomic alignment, have a constant susceptibility with temperature.
Slide 28
The concept of magnetic susceptibility is closely related to magnetism and electromagnetic waves.
Understanding the behavior of magnetic materials helps in the design and development of efficient electronic devices and communication systems.
Slide 29
Magnetic susceptibility can be measured using various techniques such as vibrating sample magnetometry, SQUID magnetometry, and magnetic torque methods.
These techniques help in accurately determining the magnetic properties of different materials.
Slide 30
In summary, magnetization is the process of aligning magnetic domains in a material, which can be achieved using an external magnetic field.
Ampere’s law relates the magnetic field around a closed loop to the current passing through the loop.
Magnetic susceptibility is a measure of how easily a material can be magnetized and is defined as the ratio of magnetization to the applied magnetic field intensity.
Materials can have positive, negative, or zero susceptibility, which influences their response to magnetic fields and finds applications in various fields of science and technology.
