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Theory of Losses

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Vatsal Manavar

The document discusses domain theory of ferromagnetism and hysteresis. It first defines key terms like ferromagnetism, domains, and hysteresis. It then explains that in ferromagnetic materials below the Curie temperature, the material consists of magnetic domains that are spontaneously magnetized in random directions. When an external magnetic field is applied, the domains begin to align with the field. This leads to hysteresis, where the magnetic flux density B lags behind changes in the applied magnetic field H, forming a hysteresis loop on the B-H graph. The size of the hysteresis loop depends on the number of domains switching direction as the field changes.

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Domain Theory of Ferromagnetism and Hysteresis Makwana Nikhil N. 150110109022 Makwana Rahil 150110109023 Manavar Vatsal A. - 150110109024
Contains Basic details of Domain Effect of External Magnetic Field on the Domains Step by step magnetization Details about Hysteresis Explanation of Hysteresis on the Basis of Domain Theory
Terminologies FERROMAGNETISM: Ferromagnetism is a phenomenon in which a material gets magnetized to a very large extent in the presence of an external field. DOMAIN: A specimen of ferromagnetic material consists of different region which are spontaneously magnetized below the Curie temperature. These spontaneously magnetized or self magnetized regions in a ferromagnetic material is called the domains. HYSTERESIS: Hysteresis is lagging (phase lagging) of magnetic induction B in ferromagnetic and ferrimagnetic materials with respect to the cyclic variation of an applied magnetic field, when the specimen is at a temperature below its Curie temperature.
DOMAINS At the lower temperature than Curie, & in the absence of an external magnetic field, the direction of magnetization of each domain have random orientation in space as shown in figure.
Effect of external magnetic field on Domain As we know that when there is no any external field applied to the material, all the domain of the ferromagnetic material are in random direction itself.
Continued But when the external magnetic field is applied to any ferromagnetic material, its domain tends to get aligned in the direction of the external field.
Continued As the external magnetic field becomes stronger, all the domains gets completely aligned in the direction of the external magnetic field.
Hysteresis As we have earlier seen that the Hysteresis is lagging (phase lagging) of magnetic induction B in ferromagnetic and ferrimagnetic materials with respect to the cyclic variation of an applied magnetic field, when the specimen is at a temperature below its Curie temperature. It is the graph of Magnetic flux density (B) versus magnetic field (H). It is also known as hysteresis curve.
Hysteresis Curve Br OHc A C
Explanation As we increase magnetic field H, value of B also increases and the curve develops along Oa. At a, if H is further increases, B remains constant. If H is done 0, then value of Ob at point b is called the RETENTIVITY. Now when the value of H is increased In the reverse direction, B becomes 0 at C point and specimen gets completely demagnetized. This value of H i.e. OC is called the coercive field Hc. This effect is called COERCIVITY. If H is further increased in reverse direction, B also increase in reverse direction and follows the path de instead of dc. Now, if H in increased in the main direction, specimen gets completely demagnetized at f. Thus variation B with respect to H traced along the closed path abcdefa in one full cycle of magnetization and demagnetization is called the hysteresis curve. The area enclosed by the curve gives the energy loss per unit volume of the material per cycle.
Hysteresis on the basis of Domain
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Theory of Losses

  • 1. Domain Theory of Ferromagnetism and Hysteresis Makwana Nikhil N. 150110109022 Makwana Rahil 150110109023 Manavar Vatsal A. - 150110109024
  • 2. Contains Basic details of Domain Effect of External Magnetic Field on the Domains Step by step magnetization Details about Hysteresis Explanation of Hysteresis on the Basis of Domain Theory
  • 3. Terminologies FERROMAGNETISM: Ferromagnetism is a phenomenon in which a material gets magnetized to a very large extent in the presence of an external field. DOMAIN: A specimen of ferromagnetic material consists of different region which are spontaneously magnetized below the Curie temperature. These spontaneously magnetized or self magnetized regions in a ferromagnetic material is called the domains. HYSTERESIS: Hysteresis is lagging (phase lagging) of magnetic induction B in ferromagnetic and ferrimagnetic materials with respect to the cyclic variation of an applied magnetic field, when the specimen is at a temperature below its Curie temperature.
  • 4. DOMAINS At the lower temperature than Curie, & in the absence of an external magnetic field, the direction of magnetization of each domain have random orientation in space as shown in figure.
  • 5. Effect of external magnetic field on Domain As we know that when there is no any external field applied to the material, all the domain of the ferromagnetic material are in random direction itself.
  • 6. Continued But when the external magnetic field is applied to any ferromagnetic material, its domain tends to get aligned in the direction of the external field.
  • 7. Continued As the external magnetic field becomes stronger, all the domains gets completely aligned in the direction of the external magnetic field.
  • 8. Hysteresis As we have earlier seen that the Hysteresis is lagging (phase lagging) of magnetic induction B in ferromagnetic and ferrimagnetic materials with respect to the cyclic variation of an applied magnetic field, when the specimen is at a temperature below its Curie temperature. It is the graph of Magnetic flux density (B) versus magnetic field (H). It is also known as hysteresis curve.
  • 10. Explanation As we increase magnetic field H, value of B also increases and the curve develops along Oa. At a, if H is further increases, B remains constant. If H is done 0, then value of Ob at point b is called the RETENTIVITY. Now when the value of H is increased In the reverse direction, B becomes 0 at C point and specimen gets completely demagnetized. This value of H i.e. OC is called the coercive field Hc. This effect is called COERCIVITY. If H is further increased in reverse direction, B also increase in reverse direction and follows the path de instead of dc. Now, if H in increased in the main direction, specimen gets completely demagnetized at f. Thus variation B with respect to H traced along the closed path abcdefa in one full cycle of magnetization and demagnetization is called the hysteresis curve. The area enclosed by the curve gives the energy loss per unit volume of the material per cycle.
  • 11. Hysteresis on the basis of Domain