Diamagnetic- Paramagnetic and Ferromagnetic Materials - Magnetic Field of the Earth

1. Diamagnetic Materials:

• Concept of Diamagnetism: Materials that exhibit repulsion from a magnetic field due to the absence of unpaired electrons and the creation of a counteracting field.

Reference: NCERT Class 12, Chapter 6 - Magnetic Effects of Current and Magnetism, pages 231-233.

• Examples and Applications:
  • Bismuth: Diamagnetic metal used in medical imaging and high-temperature superconductors.
  • Copper: Diamagnetic metal utilized in electrical wiring, electronics, and jewelry.
  • Graphite: Diamagnetic carbon material employed in pencils, lubricants, and high-temperature applications.

2. Paramagnetic Materials:

• Concept of Paramagnetism: Materials that exhibit weak attraction to a magnetic field due to the presence of unpaired electrons and their alignment with the external field.

Reference: NCERT Class 12, Chapter 6 - Magnetic Effects of Current and Magnetism, pages 233-235.

• Properties and Characteristics:

  • Susceptibility: Quantifies the degree of magnetization of a paramagnetic material in response to an external field.
  • Magnetic Moment: Represents the strength of the magnetic dipole created by the unpaired electrons.

• Examples:

  • Oxygen: Paramagnetic gas essential for respiration and combustion.
  • Aluminum: Paramagnetic metal used in various industries, such as aerospace, construction, and automotive.
  • Sodium Chloride (NaCl): Paramagnetic compound commonly known as table salt.

3. Ferromagnetic Materials

• Phenomenon of Ferromagnetism: Materials that exhibit strong and permanent attraction to a magnetic field due to the alignment of magnetic domains and exchange interactions.

Reference: NCERT Class 12, Chapter 6 - Magnetic Effects of Current and Magnetism, pages 235-239.

• Hysteresis Loop:

  • Graphical representation of the relationship between magnetic field strength (H) and magnetization (M) in a ferromagnetic material.
  • Exhibits hysteresis, indicating energy losses during the magnetization and demagnetization processes.

• Curie Temperature:

  • Temperature at which the ferromagnetic properties of a material cease, and it transforms into a paramagnetic state.

4. Earth’s Magnetic Field:

• Generation of Earth’s Magnetic Field:
  • Geodynamo: Continuous movement of molten iron in the Earth’s outer core generates electric currents, creating the Earth’s magnetic field.

Reference: NCERT Class 11, Chapter 13 - Magnetic Effects of Electric Current, pages 393-394.

• Earth’s Magnetic Field Lines:

  • Imaginary lines that represent the direction and strength of the Earth’s magnetic field at different locations.
  • Magnetic Poles: Points where the field lines converge, approximately aligning with the geographic poles.

• Magnetic Declination and Dip:

  • Magnetic Declination: Angle between the geographic north and the direction indicated by a compass needle.
  • Magnetic Dip: Angle between the Earth’s magnetic field lines and the horizontal plane.

5. Magnetic Properties of Materials:

• Comparison of Magnetic Behaviors:

  • Diamagnetic materials exhibit weak repulsion, paramagnetic materials have weak attraction, and ferromagnetic materials have strong attraction to magnetic fields.

• Electronic Structure and Atomic Arrangements:

  • Diamagnetism is due to the symmetrical electron pairing, paramagnetism arises from unpaired electrons, and ferromagnetism results from the alignment of unpaired electrons in domains.

• Measurement of Magnetic Properties:

  • Gaussmeter: Measures the strength of a magnetic field.
  • Vibrating Sample Magnetometer (VSM): Determines the magnetization of a material by vibrating it in a magnetic field.