^Comparative study of Dia, para & ferro

^Comparative study of Dia, para & ferro

Property Diamagnetic Paramagnetic Ferromagnetic
Physical state Solid, liquid or gas Solid, liquid or gas Crystalline solids only
Atomic dipole moments Zero permanent dipole moment Non – zero permanent dipole moments but oriented randomly Non – zero permanent dipole moments but organised in domains
  Effect of external mag. field Feebly repelled Feebly attracted Strongly attracted
A freely suspended rod in a uniform magnetic field A diamagnetic rod aligns  itself  normal to field A paramagnetic rod aligns  itself along field A ferromag. rod quickly aligns itself  along field
In a non uniform magnetic field Tend to move slowly from stronger to weaker field. Tend to move slowly from weaker to stronger field Tend to move quickly  from weaker to stronger.
Intensity of magnetization  Small – ve Small +ve Large +ve
Relative permeability (μr) 0 ≤ μr < 1 (slightly) μr > 1 (slightly) > 1 Quite large

( ≈ 1012)

Permeability μ < μ0 μ > μ0 μ >>μ0
Mag. susceptibility Small – ve (≈ 1) Small + ve (≈ 1) Large + ve ( ≈ 1012)
B in a medium is More than in diamagnetic Less than in a paramagnetic Much lesser in a ferromagnetic
Dependence of χm on H Independent Independent Independent
Dependence of χm on H χ ∝ T0 (Curie law) (Curie weiss)
Can be explained by Orbital motion of electrons Spin motion of e s (90%) Domain Theory
Transition No Para increases (on cooling) Ferro® para (on heating)
Effect of temperature No effect

(Except Bi at low T)

Decreases Decreases

(T=TC, F → P)

Examples People, frogs, bismuth, copper, gold, zinc, silver, Diamond, graphite, mercury, lead, water, hydrogen, nitrogen (at NTP),NaCl, CO2, benzene & all inert gases. Transition elements, rare earth elements and actinide elements, oxygen gas, air, aluminum, tungsten, titanium, cerium. Iron, cobalt, nickel, gadolinium, dysprosium, Fe2 O3, alnico and alloys containing these elements.
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