1. 부산대학교 재료공학부 계면공학 연구실 [Magnetic Properties] Chap. 5. Magnetic Properties  Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the fundamental magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. magnetic fieldsmagnetic moments Spin and orbital motion of electrons Operation principle

2. 부산대학교 재료공학부 계면공학 연구실  Hysteresis loop  Magnetization [demag- ] B[M]-H loop: B = H + 4  M Chap. 5. 재료의 자기적 특성 [Hysteresis Loop] H: applied magnetic field

3. 부산대학교 재료공학부 계면공학 연구실 [Hysteresis Loop]  Hysteresis loop: Magnetization [demagnetization] in materials Hard magnetic- : permanent magnet Soft magnetic- : recording materials Magnetic domain: the area of same spin alignment region Chap. 5. Magnetic Properties

4. 부산대학교 재료공학부 계면공학 연구실  Principle of Magnetic recording  Recording [Reading] of 0/1 [Magnetic Recording /Reading] Chap. 5. Magnetic Properties

5. 부산대학교 재료공학부 계면공학 연구실 [Microphone and Speaker] [Microphone] [Speaker] Chap. 5. Magnetic Properties

6. 부산대학교 재료공학부 계면공학 연구실  Lenz's law / ˈ l ɛ nts/ is a common way of understanding how electromagnetic circuits obey Newton's third law and the conservation of energy./ ˈ l ɛ nts/ electromagneticNewton's third law conservation of energy If an induced current flows, its direction is always such that it will oppose the change which produced it. Lenz's law is shown with the negative sign in Faraday's law of induction:Faraday's law of induction which indicates that the induced voltage ( ℰ ) and the change in magnetic flux (∂Φ) have opposite signs.  Principle of Generator and Motor by using Fleming’s Right/Left Rule [Principle of Generator / Motor] Chap. 5. Magnetic Properties

7. 부산대학교 재료공학부 계면공학 연구실 Notation: direction of current and direction of magnetic field [Principle of Generator / Motor] Chap. 5. Magnetic Properties

8. 부산대학교 재료공학부 계면공학 연구실 [Principle of Generator / Motor]  Understanding of Fleming’s Left Hand Rule for Motor [ 전동기 ] [N  S] [ +  - ] [conductor] Chap. 5. Magnetic Properties

9. 부산대학교 재료공학부 계면공학 연구실 [Principle of Generator / Motor]  Force attraction and repulsion of conductor in the magnetic field  Motion of conductor (coiled body) [  Motor] Chap. 5. Magnetic Properties

10. 부산대학교 재료공학부 계면공학 연구실  Motion of conductor (single-turn coil) [  Motion of rotor] [Principle of Generator / Motor] Chap. 5. Magnetic Properties

11. 부산대학교 재료공학부 계면공학 연구실 [Principle of Generator / Motor]  Motion of conductor (multi-turn coil) [  Motion of rotor] Chap. 5. Magnetic Properties

12. 부산대학교 재료공학부 계면공학 연구실 [Principle of Generator / Motor] How can we rotate the rotator?  Boiled water, wind, falling water? [ 수력, 풍력, 화력, 원자력 ] 발전기 Chap. 5. Magnetic Properties

13. 부산대학교 재료공학부 계면공학 연구실 [Principle of Generator / Motor]  Electro Motive Force (EMF) generation by Rotational Conductor[Coil] Chap. 5. Magnetic Properties

14. 부산대학교 재료공학부 계면공학 연구실 [Principle of Generator / Motor] Chap. 5. Magnetic Properties

15. 부산대학교 재료공학부 계면공학 연구실 Chap. 5. Magnetic Properties

16. 부산대학교 재료공학부 계면공학 연구실 [Homework #5] / Due date: before next class 1. Describe principle of microphone in terms of magnet. 2. Describe principle of speaker in terms of magnet. 3. Describe principle of magnetic recording in terms of magnet. 4. Describe principle of magnetic reading in terms of magnet. 5. Describe principle of electric motor in terms of magnet. 6. Describe principle of electric generator in terms of magnet. [Magnetic Properties] Chap. 5. Magnetic Properties