Curie temperature, reversible process

In summary, the conversation discusses the use of Curie temperatures for temperature calibration in a lab setting. The speaker has questions about the process and its accuracy. DrDu provides answers, stating that using the same piece multiple times for calibration is possible, the process is reversible but the magnetization may not be the same, and the Curie temperature can be affected by external factors or modifications to the material. The results of tests on three alloys are also discussed.
  • #1
olle3770
2
0
Hello guys, first post in this forum :)

Magnetism has always been complicated to understand for me, and I would like some help regarding Curie temperatures.

We have just bought a new measurement equipment to out lab which shall be temperature calibrated with curiepoints. We have three alloys, (Isatherm, Ni-alloy and Trafoperm).

My questions are:

* Is it possible to use the same pieces of alloy multiple times for calibration?
* Is the process reversible? i.e is the pieces as magnetic as before when cooled again?
* Is it possible to affect the Curie temperature in any way and how accurate is it?

Appreciate all help, need to explain to the chemistry guys :)

//Olle, Sweden
 
Physics news on Phys.org
  • #2
1. I don't see good reasons why you shouldn't use the same piece several times. However, I am not an experimentalist.
For example, I could imagine that there are some changes in crystal structure upon tempering which may affect the Curie point.
2. The Ferromagnetic-Paramagnetic transition is fully reversible. However, this does not mean that the pieces will be "as magnetic as before". If the material is permanently magnetized below the Curie point, this magnetization will be lost if the material is first heated and then cooled down again without an external magnetic field. However, when measuring the Curie point, you usually doing measurements in the paramagnetic region (>Tc) so there is no problem here.
3. I don't know much about it's accuracy. There are little ways to influence the Curie point. The most probable ones in the alloys you are using are formation of separate phases or formation of new crystal structures. I have no idea whether this is relevant for the alloys you are using.
 
  • #3
Thanks for the answers DrDu!

I did just receive the results from the tests when we tried heating the same pieces three times over the Curie temperatures. The isatherm and ni-alloy seemed to have a bit changed magnetic characteristics between the tests but the curie temperature remained at the same temperature. The Trafoperm did however change curie temperature, first one was about 747 the second one 748 but the third one was 767, all numbers in degrees celcius.
 
  • #4
The magnetization of the material will most likely change when you go through the Curie transition several times, as DrDu has explained. The Curie temperature is more difficult to change. For one and the same material, it can be influenced by an external magnetic field, hydrostatic pressure, or - if there is a magneto-elastic distortion associated with the phase transition - by uniaxial strain. In all these cases you need a lot of external force for a relatively small change in transition temperature. Another possibility, again as DrDu pointed out, is that you somehow modify the material. In the case of an alloy, heating ("annealing") it can change details of the composition via phase separation, etc.
 

1. What is Curie temperature?

Curie temperature is the temperature at which a material undergoes a phase transition from a ferromagnetic or ferrimagnetic state to a paramagnetic state. It is named after the physicist Marie Curie who discovered the phenomenon.

2. How is Curie temperature measured?

Curie temperature can be measured by using various techniques such as magnetic susceptibility, specific heat, and electrical resistivity. These methods involve subjecting the material to different temperatures and measuring its response to determine the temperature at which the phase transition occurs.

3. What is a reversible process in relation to Curie temperature?

A reversible process is one in which a material can be heated or cooled without any loss or gain of energy. In the case of Curie temperature, a reversible process would involve the material undergoing a phase transition from a ferromagnetic state to a paramagnetic state, and then back to its original state upon cooling.

4. Why is Curie temperature important?

Curie temperature is important in understanding and predicting the behavior of magnetic materials. It is also used in various applications such as data storage, electronic devices, and medical equipment.

5. Can Curie temperature be altered or controlled?

Yes, the Curie temperature of a material can be altered or controlled by changing its composition, crystal structure, or by applying external magnetic fields. This is known as the Curie point manipulation and is important for tailoring the properties of magnetic materials for specific applications.

Similar threads

Replies
23
Views
1K
Replies
16
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
5K
  • STEM Career Guidance
Replies
4
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
11
Views
3K
  • STEM Academic Advising
Replies
3
Views
1K
  • Sci-Fi Writing and World Building
Replies
2
Views
2K
  • STEM Career Guidance
Replies
6
Views
6K
  • Astronomy and Astrophysics
Replies
2
Views
4K
Replies
13
Views
2K
Back
Top