Cobalt is ferromagnetic, but considerably less so than iron. Alloys of cobalt such as aluminium, nickel, cobalt and iron, known as Alnico, and of samarium and cobalt (samarium-cobalt magnet) are commonly used to make high quality permanent magnets.
Magnetic lines of flux help align the magnetic domains in soft iron, increasing its magnetic permeability and making it easier for the material to become magnetized. This results in the material being strongly attracted to magnets and enhancing its magnetic properties.
Hard magnets are those which require a high magnetic field so as to be magnetized. Soft magnets are those which acquire high magnetic flux when a little magnetic force is applied onto them.
Supermalloy is a metal alloy that is 79% nickel, 5% molybdenum and 16% iron. It is used in mechanical and electronic components like hard drives. It is disigned to have a very high magnetic permeability and a low coercivity, meaning that magnetic fields can flow though it very easily. It is also a soft magnetic material, meaning that it doesn't stay magnetized itself once the magnetic field is removed.
Soft iron is having very low hysteresis loss. So it would be good to use it as core.
Plastic can be soft or hard, depending on its composition and processing. Some plastics are engineered to be flexible and soft, while others are rigid and hard.
The magnetic materials which can magnetise and de-magnetise easily are called "soft magnetic materials" example:-ferrites,iron-cobalt alloy. The magnetic materials which cannot magnetise and de-magnetise easily are called "hard magnetic materials" example:-aluminium(al),nickel-cobalt alloy.
Magnetic lines of flux help align the magnetic domains in soft iron, increasing its magnetic permeability and making it easier for the material to become magnetized. This results in the material being strongly attracted to magnets and enhancing its magnetic properties.
Colour: black, opaque. Streak: black. Lustre: metallic or dull. Cleavage: none. Hardness: 5.5-6.5. Specific Gravity: 5.2. Its diagnostic feature is that it is highly magnetic.
Iron is a soft magnetic material due to its unique crystal structure that allows its magnetic domains to easily realign in response to an external magnetic field. This property results in a high magnetic permeability and low coercivity, making iron well suited for applications where magnetic fields need to be rapidly and easily induced or changed.
Hard magnets are those which require a high magnetic field so as to be magnetized. Soft magnets are those which acquire high magnetic flux when a little magnetic force is applied onto them.
Soft magnets are easily magnetized and demagnetized, while hard magnets retain their magnetism once magnetized. Soft magnets have low coercivity and high permeability, making them suitable for applications like electromagnets. Hard magnets have high coercivity and are used in applications where a strong, lasting magnetic field is needed, such as in permanent magnets.
Materials which retain their magnetism and are difficult to demagnetize are called hard magnetic materials. These materials retain their magnetism even after the removal of the applied magnetic field. Hence these materials are used for making permanent magnets. In permanent magnets the movement of the domain wall is prevented. They are prepared by heating the magnetic materials to the required temperature and then quenching them. Impurities increase the strength of hard magnetic materials. Soft magnetic materials are easy to magnetize and demagnetize. These materials are used for making temporary magnets. The domain wall movement is easy. Hence they are easy to magnetize. By annealing the cold worked material, the dislocation density is reduced and the domain wall movement is made easier. Soft magnetic materials should not possess any void and its structure should be homogeneous so that the materials are not affected by impurities.
Coercivity is the property describing the ability of magnetic material to retain magnetism. Compared to soft iron, hard iron has larger magnetic domains, regions of the crystal where atomic magnetic fields have similar orientation. Materials with fewer, bigger domains within a given volume have higher coercivity than materials with many small domains. Hard iron can still lose its magnetism, as all permanent magnets can be demagnitized if strong enough fields are involved. Soft iron loses magnetism simply by removing it from a magnetic field. Some "rare earth" metal alloys can retain magnetism much better than hard iron, since they can have much larger domains.
Materials which retain their magnetism and are difficult to demagnetize are called hard magnetic materials. These materials retain their magnetism even after the removal of the applied magnetic field. Hence these materials are used for making permanent magnets. In permanent magnets the movement of the domain wall is prevented. They are prepared by heating the magnetic materials to the required temperature and then quenching them. Impurities increase the strength of hard magnetic materials. Soft magnetic materials are easy to magnetize and demagnetize. These materials are used for making temporary magnets. The domain wall movement is easy. Hence they are easy to magnetize. By annealing the cold worked material, the dislocation density is reduced and the domain wall movement is made easier. Soft magnetic materials should not possess any void and its structure should be homogeneous so that the materials are not affected by impurities.
Supermalloy is a metal alloy that is 79% nickel, 5% molybdenum and 16% iron. It is used in mechanical and electronic components like hard drives. It is disigned to have a very high magnetic permeability and a low coercivity, meaning that magnetic fields can flow though it very easily. It is also a soft magnetic material, meaning that it doesn't stay magnetized itself once the magnetic field is removed.
Soft iron is a good example of a material that can be strongly magnetized by an external magnetic field, but which loses most (or nearly all) of its magnetism as soon as the external field is removed. Generally, materials classed as Paramagnetic exhibit this behaviour. Many Ferromagnetic materials are designed to behave this way, such as the Ferrite cores of tuning coils in radio receivers.
Yes, all steels are magnetic. The difference is in the material being a "soft" or a "hard" magnetic material.A cold rolled mild steel, such as 1018 steel, is considered a "soft" magnetic material.I recommend reading "ASM Ready Reference: Electrical and Magnetic Properties of Metals" by Charles Moosbrugger and Fran Cverna for reference details and information. Particularly the brief section of Chapter 7 would be most helpful to you, with values in Chapter 8.