- There are four types of magnetism: superconductor, diamagnetism, paramagnetism, and ferromagnetism.
- The three naturally occurring elemental metals that are ferromagnetic are iron, nickel, and cobalt.
- Metal alloys can also exhibit magnetism, depending on the substances included in the alloy.
- Some non-metals, such as certain types of graphite, liquid oxygen, and boron fullerenes, exhibit paramagnetism or diamagnetism.
Iron, nickel, cobalt, steel, stainless steel, gadolinium, ferrite, alnico, permalloy, magnetite, and dysprosium are all magnetic metals. However, the titular question can’t be answered with a simple list. There are four types of magnetism, each present in different materials. Additionally, the term “metal” has several meanings. Let’s examine the magnetic metals in-depth.
What Is Metal?
The term metal can refer to any substance with high electrical and thermal conductivity. Metals must also offer malleability, ductility, and light reflectivity. However, “metal” can refer to metal elements, metalloids, and metal alloys.
What Is an Elemental Metal?
An elemental metal is any element on the periodic table that naturally presents itself as a metal. These substances present high density, shiny appearances, high melting points, and electric conductivity. Aside from mercury, all metals are solid at room temperature. They also form positive ions and have metallic bonds. They have these features right out of the ground.
Examples of elemental metals include iron, copper, aluminum, gold, and silver. Around 75% of the Earth’s elements are metals. The periodic table includes many varieties, like actinide, lanthanide, akali, alkaline-earth, rare, and transition metals.
What Is a Metalloid?
Simply speaking, a metalloid is an element that has features of both metals and non-metals. Some metalloids are shiny like metals, others are dull. Silicon and germanium can be used as semiconductors when certain conditions are met.
However, there are some notable features of metals that metalloids generally lack. For instance, metalloids are not malleable like metals; they are brittle like non-metals and will break when you try to bend them.
What Is a Metal Alloy?
An alloy is formed when a metal is mixed with another metal or non-metal substance. Combining the two creates a solution with some properties of each ingredient. This method is often used to create materials for industrial work and construction, as pure elemental metals tend to be unideal for these purposes.
There are three types of metal alloys: substitutional alloys, interstitial alloys, and a combination of the two former types. In a substitutional alloy, some atoms in the crystal structure are replaced with different ones. In an interstitial alloy, one substance fills the space between the atoms of another. A combination alloy would see a mixture of atomic replacement and gap filling.
Metal alloys may take features from any substance in the alloy, including magnetism. Therefore, some may be more or less magnetic than the included metals in their natural states.
How Does Magnetism Work?
Magnetism happens when electric charges on the atomic level from two opposing objects are either attracted or repelled by each other. All substances are made of tiny atoms with little electrons that carry an electric charge spinning around a nucleus.
In most items, like paper, rocks, and even people, an equal number of electrons move in either direction. So, the electrons’ charges cancel each other out, and the object’s magnetism is relatively weak. However, in substances that experience strong magnetism, the electrons typically all move in one direction (or mostly). Thus, these materials have a strong magnetic attraction.
What Are the Different Types of Magnetism?
While most people have a clear picture in their mind when they hear the word “magnet,” there are actually four different types of magnetism and one type of anti-magnetism. These classes of magnetism are present in various materials throughout our world and naturally occur in some substances. Let’s examine them.
|Type of Magnetism
|What It Means
|Magnetic fields strongly repel these substances.
|These materials are weakly repelled by magnetic fields.
|This matter type is weakly attracted to magnetic fields.
|This stuff is strongly attracted to magnetic fields. Ferromagnetic objects are typically what people think of when they think of “magnets.”
|These materials have no magnetism whatsoever. Antiferromagnetism typically occurs only under certain temperatures. Above the Néel temperature, certain antiferromagnetic materials become paramagnetic.
Now, all substances are diamagnetic. So, in that sense, all metals are magnetic. However, that’s not the question you’re asking, we know. You want to know which metals are, specifically, ferromagnetic. Admittedly, not all of them are.
What Are the Types of Magnets?
In addition to four types of magnetism, there are also three types of magnets. These are as follows:
|Type of Magnet
|What It Is
|These are naturally occurring materials that don’t lose their magnetism easily. Some may simply have strong magnetism, while others may resist attempting to change it.
|When exposed to a field, these substances become magnetic and gradually lose their magnetism when removed.
|These magnets require an electric current running through wire coils to produce magnetism.
What Is the Curie Point?
The Curie point in science is the temperature at which a substance experiences a drastic change in its magnetic properties, slowly losing its magnetism. Magnetite is a common magnetic mineral with a Curie point around 1,060°F or 580°C. If the temperature exceeds the Curie point, a hunk of magnetite will lose its ferromagnetic properties and become paramagnetic.
Magnetic rocks will generally get their properties from remnant magnetism and will lose their magnetic traits if they are heated above their Curie point.
Which Metals Are Ferromagnetic?
There are only three naturally occurring elemental metals that are ferromagnetic. They are iron, nickel, and cobalt. Alloys made with these substances, such as steel and stainless steel, can become ferromagnetic due to their inclusion in the mixture.
Gadolinium is also ferromagnetic under its Curie temperature, and we often use it in magnetic resonance imaging to improve tissue magnetic sensitivity, which aids diagnostic image quality. Dysprosium is also highly ferromagnetic under its Curie temperature. However, when these metals go above that temperature, they become paramagnetic.
Additionally, we’ve mentioned a few ferromagnetic metal alloys, such as steel and stainless steel. Permalloy, wairakite, and awaruite are other ferromagnetic alloys. Magnetite is another magnetic “metal.” However, this one isn’t actually a metal. It’s formed when iron is oxidated into iron oxide, and its chemical formula is Fe3O4.
Following is a short cheatsheet of some ferromagnetic metals, their chemical formulas, Curie temperatures (if we know them), and their uses.
|1388 K (2050°F)
|Electronics, carbon nanotubes
|1043 K (1418°F)
|Power generators, distributors, nanowires, shape-memory alloys
|627 K (669°F)
|Rapid quenching of liquid alloys
|292 K (66°F)
|Nuclear reactors, MRI contrasting
|88 K (-301°F)
|LASER, phosphor activators, metal halide lamps
|Fe + C
|1043 K (1418°F)
|Industrial materials, construction
|Fe + Cr
|1023 K (1382°F)
|Industrial materials, consumer goods
|883 K (1130°F)
|CaAl2Si4O12 · 2H2O
|Fe + Ni
|553 K – 872 K (536°F – 1110°F) *Depends on the phase
|Microwaves, single-chip electronics
|~843 K (1058°F)
|Early study of magnets
|723 K (842°F)
|Fridge magnets and other permanent magnets
|Al + Ni + Co + Fe + Ti + Cu + Nb
|1113 K (1544°F)
Are Any Non-Metals Magnetic?
We generally consider being non-magnetic a trait of non-metals. However, some types of graphite are so diamagnetic that when we expose them to appropriately strong magnets, the magnets repel so hard they appear to float. Additionally, liquid oxygen and boron fullerenes are paramagnetic. Finally, fluorographenes and hydroxyl groups can make organic magnets. However, these organic magnets are antiferromagnetic at room temperature.
The image featured at the top of this post is ©Pat_Hastings/Shutterstock.com.