Put the following statements in the correct order according to the graph in Figure 5
AThe curve moves from point “a” to point “b”.
BThe curve completes the loop.
CIncrease in the magnetizing force produces increase in magnetic flux.
DThe material is saturated in the opposite direction.
ESome of the magnetic domains have lost their alignment.
FThe material has reached the point of magnetic saturation.
GMagnetizing force increases in the positive direction.
HMagnetic domains are aligned.
IH is reduced to zero.
JThe curve moves to the point of coercivity.
10 
Speaking task. Describe the hysteresis loop using Figure 5 and the information from Exercise 9. While speaking use the following expressions.
| I would like to… | Due to…/ owing to… |
| First of all… | Therefore… |
| Further… | In conclusion I would say that… |
| Otherwise… | In summary… |
| Consequently… |
11 Speaking task. In pairs discuss the magnetic properties of materials.
Text III
1 
Work in pairs. Discuss the following items with your partner.
- The classification of materials according to their magnetic properties
- Different types of magnetic materials
Complete the table with the following elements and materials.
Aluminium, iron, bismuth, wood, cobalt, copper, diamonds, carbon, graphite, gadolinium, water, steel, nickel, chromium
| ferromagnetic materials | diamagnetic materials | paramagnetic materials | antiferromagnetic materials |
| … | … | … | … |
3 
Read the text and find the answers to the following questions.
1 What factors determine the response of materials to a magnetic field?
2 What kinds of magnetic materials are attracted by a magnet?
3 What are “permanent” magnets?
4 How does the temperature influence magnetic materials?
5 What is the Curie temperature?
6 Why are paramagnetic materials considered nonmagnetic?
7 How do diamagnetic materials respond to a magnetic field?
8 What are the applications of diamagnetic materials?
Magnetic Materials
All materials can be classified in terms of their magnetic behavior falling into one of five categories depending on their bulk magnetic susceptibility. The two most common types of magnetism are diamagnetism and paramagnetism, which account for the magnetic properties of most of the periodic table of elements at room temperature (see Figure 6).
Materials respond differently to the force of a magnetic field. A magnet will strongly attract ferromagnetic materials, weakly attract paramagnetic materials, and weakly repel diamagnetic materials. The orientation of the spin of the electrons in an atom, the orientation of the atoms in a molecule or alloy, and the ability of domains of atoms or molecules to line up are the factors that determine how a material responds to a magnetic field. Ferromagnetic materials have the most magnetic uses. Diamagnetic materials are used in magnetic levitation and MRI.
Ferromagnetic materials
Ferromagnetic materials are strongly attracted by a magnetic force. The elements iron (Fe), nickel (Ni), cobalt (Co) and gadolinium (Gd) are such materials.
The reasons these metals are strongly attracted are because their individual atoms have a slightly higher degree of magnetism due to their configuration of electrons, their atoms readily line up in the same magnetic direction, and the magnetic domains or groups of atoms line up more readily.
Iron is the most common element associated with being attracted to a magnet. Steel is also a ferromagnetic material. It is an alloy or combination of iron and several other metals, giving it greater hardness than iron, as well as other specialized properties. Because of its hardness, steel retains magnetism longer than iron.
Alloys of iron, nickel, cobalt, gadolinium and certain ceramic materials can become "permanent" magnets, such that they retain their magnetism for a long time.
Strongly magnetic ferromagnetic materials like nickel or steel lose all their magnetic properties if they are heated to a high enough temperature. The atoms become too excited by the heat to remain pointing in one direction for long.
The temperature at which a metal loses its magnetism is called the Curie temperature, and it is different for every metal. The Curie temperature for nickel, for example, is about 350°C.
Antiferromagnetism
In the periodic table the only element exhibiting antiferromagnetism at room temperature is chromium. Antiferromagnetic materials are very similar to ferromagnetic materials but the exchange interaction between neighbouring atoms leads to the anti-parallel alignment of the atomic magnetic moments. Therefore, the magnetic field cancels out and the material appears to behave in the same way as a paramagnetic material. Like ferromagnetic materials these materials become paramagnetic above a transition temperature, known as the Néel temperature, TN. (Cr: TN =37ºC).
Paramagnetic materials
Paramagnetic materials are metals that are weakly attracted to magnets. Aluminum and copper are such metals. These materials can become very weak magnets, but their attractive force can only be measured with sensitive instruments.
Temperature can affect the magnetic properties of a material. Paramagnetic materials like aluminum and copper become more magnetic when they are very cold.
The force of a ferromagnetic magnet is about a million times that of a magnet made with a paramagnetic material. Since the attractive force is so small, paramagnetic materials are typically considered nonmagnetic.
Diamagnetic materials
Certain materials are diamagnetic, which means that when they are exposed to a strong magnetic field, they induce a weak magnetic field in the opposite direction. In other words, they weakly repel a strong magnet. Some have been used in simple levitation demonstrations.
Two of the strongest diamagnetic materials are carbon graphite and bismuth. Other weaker diamagnetic materials include water, diamonds, wood and living tissue. Note that the last three items are carbon-based.
The electrons in a diamagnetic material rearrange their orbits slightly creating small persistent currents which oppose the external magnetic field.
Although the forces created by diamagnetism are extremely weak – millions of times smaller than the forces between magnets and ferromagnetic materials like iron, there are some interesting uses of those materials.
The most popular application of diamagnetic materials is magnetic levitation, where an object will be made to float in or above a strong magnet. Although most experiments use inert objects, researchers as the University of Nijmegen in the Netherlands demonstrated levitating a small frog in a powerful magnetic field.
Ferrimagnetism
Ferrimagnetism is only observed in compounds, which have more complex crystal structures than pure elements.