Why do ferrofluids exhibit magnetic properties?

Why do ferrofluids exhibit magnetic properties?

When there’s no magnet around, ferrofluid acts like a liquid. The magnetite particles move freely in the fluid. But when there’s a magnet nearby, the particles are temporarily magnetized. They form structures within the fluid, causing the ferrofluid to act more like a solid.

Can ferrofluids be controlled by magnets?

Because ferrofluids are very easily magnetized (they have an incredibly high magnetic susceptibility), the peaks can be produced using a small bar magnet. Upon application of an external magnetic field, the nanoparticles align with the field.

What happens to the state of a ferrofluid when it is exposed to a magnetic field?

Background: Ferrofluid is a colloidal suspension that usually consists of surfactant-coated nanoparticles of magnetite (Fe3O4) in a carrier liquid. Ferromagnetic fluid forms spikes when the liquid is exposed to a magnetic field. Results: As the magnet approached the liquid, the ferrofluid became magnetized.

Are ferrofluids ferromagnetic?

Ferrofluid is a liquid that is attracted to the poles of a magnet. It is a colloidal liquid made of nanoscale ferromagnetic, or ferrimagnetic, particles suspended in a carrier fluid (usually an organic solvent or water). Each magnetic particle is thoroughly coated with a surfactant to inhibit clumping.

How are ferrofluids made?

Ferrofluids are made up of tiny magnetic fragments of iron suspended in oil (often kerosene) with a surfactant to prevent clumping (usually oleic acid). The oily fluid prevents debris from entering hard drives when a small amount is placed between the magnets and shaft.

Are ferrofluids toxic?

Ingestion: This material has minimal toxicity, but fluid aspirated into lungs during ingestion could cause severe pulmonary injury or death. Do not induce vomiting; seek immediate medical attention.

How does ferrofluid impact society?

When a ferrofluid is placed near a magnet, the magnet attracts the iron-containing particles. And this makes ferrofluids useful in many industries. Ferrofluids are used as liquid seals to keep dust out of computer hardrives. They can also be used in loudspeakers to help keep them cool.

Why are ferrofluids important?

A major benefit of ferrofluid is that the liquid can be forced to flow via the positioning and strength of the magnetic field and so the ferrofluid can be positioned very exactly. Ferrofluids also have the capability of reducing friction, making them useful in a variety of electronic and transportation applications.

How do you make ferrofluids?

Pour a bit of vegetable oil into a shallow dish, just enough to make a thin film across the bottom. Pour iron filings into the oil and mix the two until they have become a thick, sludge-like material. This is your ferrofluid!

How does a Ferrofluidic seal work?

A Ferrofluidic® seal takes advantage of the response of a magnetic fluid to an applied magnetic field. When fluid is applied to this gap it assumes the shape of a liquid O-ring and produces a hermetic seal.

What force plays a role with ferrofluids?

On a fundamental level these would be the van der Waals force (attractive/repulsive forces between molecules), gravity and the magnetic force. In this case, the first two forces (van der Waals and gravity) manifest themselves as surface tension and play a very big role in how the Ferrofluid spikes.

Who discovered ferrofluids?

Steve Papell
The first ferrofluid was invented by a NASA engineer named Steve Papell in the early 1960s. His idea was that if you add these magnetic nanoparticles to fuel, you can move it around in zero gravity with a magnetic field. That didn’t really pan out. But since then, ferrofluids have been used far and wide.

What are magneto-optic effects?

The research activities on the phenomenon of Magneto-optic Effects has recently promulgated due to its versatile use in magneto-optic recordings for high density magnetic data storage, magnetic field sensors and its applications in magneto-electronics.

What is the Faraday magneto-optical effect?

This separates the Faraday magneto-optical effect from natural optical activity in chiral media, that is, an optical rotation produced without an external magnetic field applied, which arises from the low symmetry of individual molecules or from the symmetry of the unit cell in a crystal [13, 14].

Can optical cross effects be realized via external fields?

Moreover, it initiated a research for materials showing optical cross effects, in which the fast manipulation of the light beam in sense of its intensity or its polarization can be realized via external fields.

What are the applications of magneto-optic crystal?

Nowadays, crystals showing large magneto-optical effects are widely used in optical isolators (Faraday rotators, optical circulators), mode-conversion waveguides and optical data storage [4]. 2. Theory of Magneto-Optic Phenomena