physics

Magnetomechanical effect

Magnetomechanical effect is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Magnetomechanical effect rather than just read about it. In short: In magnetism, a magnetomechanical effect or a magnetoelastic effect is a phenomenon of changing the magnetic properties of ferromagnetic materials by applying external stresses. The application of external stresses alters the flux density of a magnetized ferromagnet, and thus the shape, and size of its hysteresis loops.

Key takeaways

Magnetomechanical effect belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Magnetomechanical effect to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Magnetomechanical effect from memory before moving on to harder problems.

Reference excerpt

In magnetism, a magnetomechanical effect or a magnetoelastic effect is a phenomenon of changing the magnetic properties of ferromagnetic materials by applying external stresses. The application of external stresses alters the flux density of a magnetized ferromagnet, and thus the shape, and size of its hysteresis loops. Various effects exist, depending on the material. The first person to identify a magnetomechanical effect was James Prescott Joule in 1842.

Effects Magnetomechanical effects connect magnetic, mechanical and electric phenomena in solid materials. Examples include

Magnetostriction and inverse magnetostrictive effect Magnetostriction, also known as Joule magnetostriction, is the few parts per million change in the length of a ferromagnetic rod upon magnetization. The inverse magnetostrictive effect (also known as Villari effect, after Emilio Villari) is the change in magnetization in response to compressive stress. Magnetostriction is thermodynamically opposite to inverse magnetostriction effect.

Torque effects Wiedemann effect (named after Gustav Heinrich Wiedemann) is the twist in a ferromagnetic rod carrying a current induced by magnetization. The Matteucci effect (named after Carlo Matteucci) is the inverse effect. The effect of creating a magnetization by twisting a rod that is longitudinally magnetized is sometimes called the Wertheim effect (after Guillaume Wertheim).

ΔE effect The Guillemin effect is the tendency of a previously bent rod to straighten when exposed to a strong magnetic field along its axis. It was first reported by Claude-Marie Guillemin in 1846 in the specific form of the change in the deflection of an iron cantilever when subjected to a coaxial magnetic field. It was later generalized and called the ΔE effect, where it refers to changes to E, the Young's modulus. Longitudinal current can cause a similar change in deflection.

Volume effects A change in volume due to the application of a magnetic field is called the Barret effect (after William F. Barrett who presented it 1882). The reciprocal effect is called the Nagaoka–Honda effect (named after Hantaro Nagaoka and Kotaro Honda in 1898).

See also Magnetocrystalline anisotropy Magnetohydrodynamics Electrohydrodynamics

References

Worked examples

Example 1 — a first encounter with Magnetomechanical effect

Start with the simplest possible case. Write down what Magnetomechanical effect claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Magnetomechanical effect before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Magnetomechanical effect ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Magnetomechanical effect

In research: Magnetomechanical effect appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Magnetomechanical effect in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Magnetomechanical effect is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electromagnetism stubs, Magnetic ordering, Magnetism, so understanding it makes those chapters shorter.
In everyday life: Look for Magnetomechanical effect outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Magnetomechanical effect in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Magnetomechanical effect means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Magnetomechanical effect out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Magnetomechanical effect in simple terms?

Why does Magnetomechanical effect matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Magnetomechanical effect?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Magnetomechanical effect.