Einstein-De Hass Effect: Explained and Explored | Research Project Guide

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Discussion Overview

The discussion centers around the Einstein-De Haas effect, a magneto-mechanical phenomenon observed in ferromagnetic materials when subjected to an external magnetic field. Participants seek to understand the effect's principles, experimental setups, and related resources for a research project.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related
  • Experimental/applied

Main Points Raised

  • One participant expresses confusion about the Einstein-De Haas effect and requests further information and resources.
  • Another participant explains that the effect involves the alignment of atomic spins in a ferromagnet under an external magnetic field, leading to a change in angular momentum and observable rotation of the magnet.
  • A participant humorously questions if the effect is also known as the "Einstein - Hare effect," indicating a potential misunderstanding or jest.
  • A later reply reiterates the explanation of the effect, emphasizing the transition from paramagnetic to ferromagnetic states and the conservation of total angular momentum.
  • One participant describes a home experiment involving a coiled wire and an iron rod but reports no observable effect when current is passed through the coil.

Areas of Agreement / Disagreement

Participants generally agree on the basic principles of the Einstein-De Haas effect, but there is no consensus on the effectiveness of the home experiment described, as one participant reports no observable results.

Contextual Notes

The discussion includes various assumptions about the experimental setup, such as the adequacy of the materials used and the conditions under which the effect should be observable. There are also unresolved questions regarding the effectiveness of the described home experiment.

hershal
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:confused: I have a research project to be done and I want to know what is Einstein-De Hass Effect. It is magneto-mechanical effect, something happens on suspending iron rod in a ring magnet but i don't have any further information on it . If I can get some links which explains what is einstein-De Hass Effect. I searched on google, but got no good results :frown:
 
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Hi, it is the Einstein de Haas-effect

If you have a ferromagnet (that is a material in which neigboring atoms tell their closest neigbors to align their spins in the same direction) and you apply an external B field to align the spins, they will add up to produce a change in angular momentum (you know : J = L+S where S is the spin and L is the angular momentum, J is the TOTAL angular momentum), manifested by the rotation of the magnet.

Here is how it goes :

S changes due to the transition from paramagnetic to ferromagnetic (all spins align). But J must remain constant and therefore L must change and this means that the specimen will rotate. You can actually observe this rotation.

The experiment is conducted by hanging some ferromagnetic specimen (that is initially in its paramagnetic state, if you will) on a small string and then applying the external magnetic field B.

regards
marlon
 
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marlon said:
Hi, it is the Einstein de Haas-effect

Aka the Einstein - Hare effect ? :smile:
 
Thanks !

marlon said:
Hi, it is the Einstein de Haas-effect

If you have a ferromagnet (that is a material in which neigboring atoms tell their closest neigbors to align their spins in the same direction) and you apply an external B field to align the spins, they will add up to produce a change in angular momentum (you know : J = L+S where S is the spin and L is the angular momentum, J is the TOTAL angular momentum), manifested by the rotation of the magnet.

regards
marlon

Thanks Marlon, If you are aware of any site that offers information about einstiein - de Hass effect or u know any other a-z physics site could you please pass me the URL :rolleyes:
 
Home Experiment

Today, I took a transparent light weight plastic hollow cylinder ( about 3.5 cm in diameter and 15 cm in length and may be 0.5 mm thick) . Tightly coiled a wire ( simple electric wire ) around it . No. of turns are 50 . Suspend an iron rod in between ( so that it does not touch the edges of the cylinder ) with the help of a thinnest thread available at home. Iron rod is about 15.5 cm in length and 0.4 cm in diameter , quiet heavy too, with flat edges , actually its a screw driver without the plastic handle. Passed current through the coil ( 4.5 V ) ... no effect :frown::confused:
 
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