The document provides an overview of magnetic materials and their properties, detailing various types such as paramagnetic, diamagnetic, ferromagnetic, antiferromagnetic, and ferrimagnetic materials. It also explains magnetic dipoles, magnetic domains, and the B-H curve, which illustrates hysteresis in magnetic materials. Key concepts include spontaneous magnetization and magnetic susceptibility, along with their relevance to magnetic behavior.

1. ELECTRICAL
ENGINEERING
by - Mohammed Waris Senan

2. Mohammed Waris Senan 2
MAGNETIC MATERIALS
&
B-H CURVE

3. Content
Magnetic Dipole and Dipole Moment
Magnetic Materials and their properties
Magnetic Domain (Domain Theory)
B-H Curve or Hysteresis Loop
Hysteresis Loss
Mohammed Waris Senan 3

4. Mohammed Waris Senan 4
Magnetic Dipole Moment
+
e
NS
S N
S
DIPOLE
Dipole Moment, M = NIA
Direction of Dipole Moment is from S-Pole to N-Pole
Every substance has Magnetic Dipole Moment

5. Mohammed Waris Senan 5
Magnetic Materials
 Every substance contains magnetic dipole.
 The dipoles are arranged in random orientations.
 Due to random orientation some materials cancel out the dipole moments and some posses resultant dipole
moment.
 When Magnetic field is applied, dipoles try to align themselves in the direction of applied magnetic field.
NS
)B(H

or
H

MR= 0≠

6. Mohammed Waris Senan 6
Magnetic Materials contd..
 Paramagnetic Materials
 Gets weakly magnetise in the direction of applied magnetic field i.e. weakly attracted by the magnet.
 Examples: Aluminium, Manganese, Platinum etc.
 Diamagnetic Materials
 Gets weakly magnetise in opposite direction of applied magnetic field i.e. weakly repelled by the magnet.
 Examples: Copper, Phosphorous, Antimony etc.
 Ferromagnetic Materials
 Gets strongly magnetise in the direction of applied magnetic field i.e. strongly attracted by the magnet.
 Examples: Iron, Nickel, Cobalt & their alloys.
 Antiferromagnetic Materials
 Gets strongly magnetise in the opposite direction of applied magnetic field i.e. strongly repelled by the
magnet.
 Examples: Chromium, Nickel Oxide (NiO), Chromium Oxide (Cr2O3) etc.
 Ferrimagnetic Materials
 Very similar to Ferromagnetic materials but Gets not that strongly magnetise in the direction of applied
magnetic field as a Ferromagnetic material
 Examples: Ferrites like barium ferrite, magnetite etc.

7. Mohammed Waris Senan 7
Magnetic Domain
H

MR= 0≠
Magnetic
Domain
 Magnetic Domain:
Group of dipoles arranged in a particular direction
 Spontaneous Magnetization (Msp):
Resultant dipole moment present when no external
magnetic field is applied.
 Magnetic Susceptibility (χm):
Quantitative measure of the extent to which a material may
be magnetized in relation to a given applied magnetic field.
Mathematically, χm=
𝑀𝑎𝑔𝑛𝑒𝑡𝑖𝑧𝑎𝑡𝑖𝑜𝑛 (𝑀)
𝑀𝑎𝑔𝑛𝑒𝑡𝑖𝑐 𝐹𝑖𝑒𝑙𝑑 𝑆𝑡𝑟𝑒𝑛𝑔𝑡ℎ (𝐻)

8. Mohammed Waris Senan 8
B-H Curve
abe
NS
a b
i
l
Ni
H  iH 
A

B B 

9. Mohammed Waris Senan 9
B-H Curve contd..
i
t
)( B
)( iH 
Im
- Im
- Im Im
Retentivity (Br)
Coercivity (Hc)

10. Mohammed Waris Senan 10
B-H Curve contd..
)( B
)( iH 
- Im Im
H = 0
&
B ≠ 0
H ≠ 0
&
B = 0
 B becomes ZERO after H i.e. B lags H or B
hysteresis H.
 B-H curve is also called as HYSTERESIS
LOOP.
H
i
t
Hysteresis Loss
Hysteresis Loss is proportional to the area of loop
P
Q