The question of whether silver or nickel is used more in magnets has a clear answer: nickel is relevant to magnetic applications, while silver is not. Nickel is one of only three elements that exhibit ferromagnetism at room temperature, a property allowing materials to form permanent magnets or be strongly attracted to them. Silver, by contrast, is classified as diamagnetic, meaning it is inherently non-magnetic and is weakly repelled by a magnetic field. However, neither pure nickel nor silver are the dominant materials in the high-volume magnets that power modern technology. The vast majority of today’s magnets rely on complex alloys and compounds that surpass the magnetic performance of pure nickel.
Ferromagnetic Properties of Nickel
Nickel is intrinsically magnetic because of the alignment of electron spins within its atomic structure, specifically in its 3d orbital. This spontaneous alignment of magnetic moments creates microscopic regions called domains, which is the defining characteristic of ferromagnetism. As one of the core ferromagnetic elements, alongside iron and cobalt, nickel forms the basis for numerous magnetic components and alloys.
The magnetic strength of pure nickel is significantly lower than that of iron, and it possesses a lower Curie temperature, the point where a material loses its ferromagnetic properties. Nickel’s Curie temperature is relatively low at approximately 358°C, which is substantially below the 770°C point for pure iron. Above this temperature, the thermal energy is sufficient to disrupt the ordered alignment of the magnetic domains, causing the material to become paramagnetic, or only weakly magnetic.
While pure nickel is rarely used for high-strength permanent magnets, its alloys are widely deployed in specific applications. Nickel is a primary component in soft magnetic materials like Permalloy, an alloy of nickel and iron known for its high magnetic permeability and low coercivity. These qualities make it ideal for magnetic shielding, where it efficiently channels or deflects external magnetic fields, and in sensitive electronic components requiring a rapid magnetic response. Nickel is also a component in the historic Alnico magnet, which contains aluminum, nickel, and cobalt.
Silver’s Non-Magnetic Role
Silver is a diamagnetic material, which means it has a weak, negative susceptibility to magnetic fields. This property is a result of silver’s electron configuration, where all its electrons are paired, effectively canceling out any inherent magnetic moment. When exposed to an external magnetic field, the paired electrons generate a slight magnetic field that opposes the external one, resulting in a subtle repulsive force.
This repulsion is extremely weak, making silver unsuitable for use as a magnet or a material strongly attracted to one. Silver’s main importance in systems involving magnetism comes from its exceptional electrical conductivity, the highest of any metal. In devices that create a magnetic field, such as high-performance electromagnets or motors, silver is used in windings or contacts to efficiently transmit the current that generates the field.
Silver’s lack of magnetic interference is also a benefit in sensitive measurement equipment. Its diamagnetic nature ensures that components made of silver do not distort or interfere with the magnetic fields being measured or generated in devices like magnetic sensors or medical imaging equipment.
Primary Materials in Modern Magnets
The materials that dominate the modern magnet industry are not pure nickel or silver, but rather a variety of sophisticated compounds and alloys engineered for specific performance characteristics. The magnetic landscape is primarily defined by three major types: Rare Earth, Ferrite, and Alnico magnets. Rare Earth magnets, specifically Neodymium Iron Boron (NdFeB), represent the peak of modern magnetic strength.
Neodymium magnets are composed mainly of neodymium, iron, and boron, forming the chemical compound Nd2Fe14B. These magnets possess the highest magnetic energy density available, making them indispensable in high-tech applications such as electric vehicle motors, wind turbines, hard drives, and compact consumer electronics. Their immense strength allows for the miniaturization of devices, though they are susceptible to corrosion and can lose strength at relatively lower temperatures.
Ferrite, or ceramic, magnets are the most widely produced type globally, valued for their low cost and high volume of use. They are made primarily from iron oxide mixed with either strontium or barium carbonate. Although magnetically weaker than Rare Earth magnets, ferrite magnets offer excellent resistance to demagnetization, corrosion, and high temperatures, with a maximum working temperature around 250°C. They are the standard for many household items, including refrigerator magnets, loudspeakers, and small motors.
The third major category is Alnico, an alloy of aluminum, nickel, and cobalt, with iron making up the majority. Alnico magnets are historically significant and still used today, particularly in applications requiring stability over a wide temperature range, sometimes up to 550°C. While they are not as strong as Neodymium magnets, their excellent temperature stability makes them a choice for sensors, instrumentation, and certain aerospace components.