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प्रश्न
What happens to a ferromagnetic material when its temperature increases above curie temperature?
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उत्तर
A ferromagnetic material is made up of small regions known as domains. The atomic magnetic moments of nearest-neighbour atoms interact strongly within each domain via exchange interaction, a quantum mechanical phenomenon, and align parallel to each other even in the absence of an external magnetic field. As a result, a domain is spontaneously magnetised to saturation.
Only up to a specific temperature does the material keep its domain structure. When heated, the increased thermal agitation opposes spontaneous domain magnetization. Finally, at a critical temperature known as the Curie point or Curie temperature, thermal agitation overcomes the exchange forces and maintains the atomic magnetic moments randomly oriented. As a result, the material becomes paramagnetic above the Curie point. The ferromagnetic to paramagnetic transition is a transition from order to disorder. The material becomes ferromagnetic again when cooled below the Curie point.
संबंधित प्रश्न
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| List-I (Material) | List-II (Susceptibility) | ||
| A. | Diamagnetic | I. | χ = 0 |
| B. | Ferromagnetic | II. | 0 > χ ≥ −1 |
| C. | Paramagnetic | III. | χ >> 1 |
| D. | Non-magnetic | IV. | 0 < χ < ε |
Choose the correct answer from the options given below:
