Magnetic properties of the substance

Содержание и основные понятия

The substance changes the magnetic field because of orbital motion and electron backs. Reactions can weaken the field, increase it slightly, or create sustainable domains.
GEF · 11 grade
PIF · Baseline
Interactive model
Diamagnetic
Paramagnetic
Ferromagnetic
Domain
hysteresis
01
The physical picture
What happens and what boundaries the model has.
Main message
The substance changes the magnetic field because of orbital motion and electron backs. Reactions can weaken the field, increase it slightly, or create sustainable domains.
Diamagnetics are weakly pushed out of a strong field.
Paramagnetics are weakly drawn and lose their magnetity without a field.
Ferromagnetics have domains, hysteresis, and Curie's temperature.
How to reason
First, name the system and the interaction, then select the values, and only then write down the law. The formula works within the model's assumptions.
02
Laws and values
Symbols should be read as a relationship of values, not as a recipe for substitution.
B
=
μ
μ
0
H
B = \mu\mu_0 H
B
=
μ
μ
0
​
H
Field in environment
μ
=
B
B
0
\mu = \frac{B}{B_0}
μ
=
B
0
​
B
​
relative permeability
Review of the situation
The transformer's heart is made of magnetic material to reduce the loss of magnetization.
04
Links and application
In the real world
The transformer's heart is made of magnetic material to reduce the loss of magnetization.
Model verification
Compare the prediction with observation, evaluate the units, the order of magnitude and the influence of the factors not taken into account. Disparity does not always mean an error of law: often idealization is no longer sufficient.
C
What needs to be understood
Outcome 1
Explain the physical meaning of the topic "Magnetic properties of the substance" through the model, not just through the formula.
Outcome 2
Distinguish and correctly use terms: Diamagnetic, Paramatic, Ferromagnetic.
Outcome 3
Indicate the conditions for the applicability of the law, verify units and limit cases.
T
Terms of the topic
The definition should indicate the physical meaning, not a substitute for a domestic synonym.
Diamagnetic
A substance which magnetizes against the direction of the external magnetic field and is not readily pushed out of it.
Paramagnetic
A substance that is slightly magnetizing in the direction of the external magnetic field.
Ferromagnetic
A substance with a domain structure capable of highly magnetizing and maintaining residual magnetity.
Domain
The area of the Ferromagnetics, within which the magnetic moments tend to be oriented in the same way.
hysteresis
The state of the system depends not only on the current impact, but also on the previous history.
F
Origin and conclusion of the formulas
The fundamental law cannot be "proven" by algebras: for each record, it is stated whether it is a definition, an experimental law, or a model effect.
B
=
μ
μ
0
H
B = \mu\mu_0 H
B
=
μ
μ
0
​
H
empirical law
The field is Wednesday.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
B
0
=
μ
0
H
B_0=\mu_0H
B
0
​
=
μ
0
​
H
With the same tension H in the vacuum magnetic induction is μ0H.
μ
=
B
B
0
\mu=\frac{B}{B_0}
μ
=
B
0
​
B
​
Relative magnetic permeability compares a substance's response to a vacuum.
B
=
μ
B
0
=
μ
μ
0
H
B=\mu B_0=\mu\mu_0H
B
=
μ
B
0
​
=
μ
μ
0
​
H
The setting of the μ definition gives a material relationship for the linear environment.
Conditions:
A homogeneous isotropic linear magnetic medium; μ is considered constant. For herromegnetics with saturation and hysteresis, the formula is not applicable in this form.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
μ
=
B
B
0
\mu = \frac{B}{B_0}
μ
=
B
0
​
B
​
definition
Relative permeability.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
B
0
=
μ
0
H
B_0=\mu_0H
B
0
​
=
μ
0
​
H
First they find B0 induction in the vacuum at the specified H voltage.
μ
:
=
B
B
0
\mu:=\frac{B}{B_0}
μ
:=
B
0
​
B
​
The disproportional ratio of inductions is assumed to be the relative magnetic permeability of the substance.
Conditions:
B and B0 are compared with the same H and field geometry; the scalar μ implies isotropic environment.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
!
Model boundaries and typical errors
Error: Forget model condition
You can't put the formula on any situation just because it's a coincidence of letters. The key condition of this topic is that the Diamagnetics are not easily pushed out of a strong field.
How to Check the Mind
Paramagnetics do not fit in very well and lose their magnetity without field. Then check the units, vector direction, and behavior of the result at zero or very large parameter.
Σ
Conclusion on the topic
Magnetic properties of the substance
The substance changes the magnetic field because of orbital motion and electron backs. Reactions can weaken the field, increase it slightly, or create sustainable domains.
Diamagnetics are weakly pushed out of a strong field.
Paramagnetics are weakly drawn and lose their magnetity without a field.
Any numerical result shall be accompanied by a unit, a sign and an explanation of its physical meaning.
The content is consistent with the FRP on Physics of the OS/OSS 2025 and the subject matter of the current lines of the PNP: I. M. Peryškin and co-authors (7–9), G. J. Mäkishev and coauthors (10–11), and with the lines "Engineers of the Future" and V. A. Kasyanov. The original texts are not reproduced, the text of the textbooks is not reproduced.