# What is the Difference Between Magnetic Permeability and Susceptibility

The main difference between magnetic permeability and susceptibility is that magnetic permeability is a measure of a material’s ability to permit the flow of magnetic lines of flux, while susceptibility quantifies the degree of magnetization a material exhibits in response to an applied magnetic field.

Magnetic permeability and susceptibility are key properties that describe how materials interact with magnetic fields. Understanding these properties is crucial in various fields, including physics, engineering, as well as materials science, where the behavior of materials in magnetic environments is of paramount importance.

### Key Areas Covered

1. What is Magnetic Permeability
– Definition, Features, Applications
2. What is Magnetic Susceptibility
– Definition, Features, Applications
3. Similarities Between Magnetic Permeability and Susceptibility
– Outline of Common Features
4. Difference Between Magnetic Permeability and Susceptibility
– Comparison of Key Differences
5. FAQ: Magnetic Permeability and Susceptibility
– Frequently Asked Questions

### Key Terms

Absolute Permeability, Magnetic Permeability, Magnetic Susceptibility, Relative Permeability

## What is Magnetic Permeability

Magnetic permeability is a fundamental property of materials that describes their ability to allow the passage of magnetic flux. It is a key parameter in understanding and engineering magnetic systems. The concept is particularly crucial in the study of electromagnetism, where the response of materials to magnetic fields plays a pivotal role.

Defined as the ratio of the magnetic flux density to the magnetic field strength within a material, magnetic permeability is denoted by the symbol μ. In fact, in simple terms, it quantifies how easily a material can be magnetized. Materials with high permeability allow magnetic lines of force to pass through them more readily than materials with low permeability.

There are two main types of magnetic permeability: absolute permeability (μ) and relative permeability (μr). Absolute permeability measures the ability of a material to carry magnetic flux and is expressed in units of Henrys per meter (H/m). Relative permeability, on the other hand, is the ratio of a material’s permeability to the permeability of a vacuum. Moreover, it is a dimensionless quantity often represented by the symbol μr.

Understanding magnetic permeability is essential in the design and optimization of magnetic circuits, transformers, and inductors. Generally, materials like iron and other ferromagnetic substances exhibit high permeability, making them ideal for applications where strong magnetic effects are desired. Conversely, non-magnetic or weakly magnetic materials have low permeability and are used in applications where magnetic interference needs to be minimized.

## What is Magnetic Susceptibility

Magnetic susceptibility is a property of materials describing their ability to become magnetized in the presence of an external magnetic field. It is a fundamental parameter in the study of magnetism and is defined as the ratio of the material’s magnetization to the applied magnetic field strength. Symbolized by the Greek letter χ (chi), magnetic susceptibility can be positive, negative, or even zero, indicating how a material responds to an external magnetic field.

Materials with positive magnetic susceptibility are attracted to a magnetic field and tend to become magnetized in the direction of the applied field. In contrast, materials with negative susceptibility are repelled by the field and align themselves in the opposite direction. The magnitude of magnetic susceptibility also provides insight into the material’s ability to enhance or oppose magnetization.

The susceptibility of a substance is influenced by its atomic and molecular structure. In paramagnetic materials, individual atomic magnetic moments align with the external field, resulting in a positive susceptibility. Moreover, ferromagnetic materials exhibit a strong positive susceptibility, often leading to spontaneous magnetization even in the absence of an external field. Antiferromagnetic and diamagnetic materials, on the other hand, typically display negative susceptibilities.

Scientists and engineers use magnetic susceptibility measurements to understand the magnetic properties of various substances. Magnetic susceptibility also plays a crucial role in diverse fields, including geophysics, material science, and medical imaging. In geophysics, it aids in studying the composition of rocks and minerals. Furthermore, in medical applications, magnetic susceptibility is relevant to magnetic resonance imaging (MRI), where it influences image contrast and resolution.

## Similarities Between Magnetic Permeability and Magnetic Susceptibility

• Both represent the extent to which a material can be magnetized.
• Moreover, both are properties that depend on the material in question.
• In addition, they can be influenced by changes in temperature, impacting their values.

## Difference Between Magnetic Permeability and Magnetic Susceptibility

### Definition

Magnetic permeability is a measure of how easily a material can become magnetized in the presence of an external magnetic field. Magnetic susceptibility, on the other hand, is a dimensionless proportionality constant that indicates the degree of magnetization a material exhibits in response to an applied magnetic field.

### Measurement

Magnetic permeability is measured in units of Henrys per meter (H/m) or Tesla meter per Ampere (T·m/A), while magnetic susceptibility is a dimensionless quantity; it has no units.

### Nature

While magnetic permeability is directly related to the overall magnetization of a material in response to an external magnetic field, magnetic susceptibility specifically quantifies the extent to which the material becomes magnetized.

## FAQ: Magnetic Permeability and Magnetic Susceptibility

### What is the formula for magnetic permeability?

μ = B/H is the formula for magnetic permeability.

### What is the application of magnetic permeability?

The main application of magnetic permeability is the characterization of magnetic materials.

### How do you measure magnetic permeability?

There are many methods to measure magnetic permeability but the most common method is the magnetic balance method.

## Conclusion

In brief, magnetic permeability is the ability of a material to allow the passage of magnetic lines of force. Magnetic susceptibility, on the other hand, measures how easily a material can be magnetized in the presence of an external magnetic field. Thus, this is the main difference between magnetic permeability and susceptibility.

##### Reference:

1.  “Magnetic Susceptibility.” Byju’s.

##### Image Courtesy:

1. “VFPt flat cylinder magnet” By Geek3 – Own work (CC BY-SA 4.0) via Commons Wikimedia

### About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.