Which of the following statements are correct ?

Options

A. Ferrimagnetic substances lose ferrimagnetism on heating and become paramagnetic
B. Ferrimagnetic substances do not lose ferrimagnetism on heating and remain ferrimagnetic
C. Antiferromagnetic substances have domain structures similar to ferromagnetic substances and their magnetic moments are not cancelled by each other
D. In ferromagnetic substances all the domains get oriented in the directionof magnetic field and remain as such even after removing magnetic field.

Answer

To solve the question regarding which statements about magnetic substances are correct, we will analyze each option step by step.

### Step 1: Analyze Option A
**Statement:** "Ferromagnetic substances lose ferrimagnetism on heating and become paramagnetic."

- **Explanation:** Ferromagnetic substances have a strong magnetic ordering due to the alignment of their magnetic moments. When heated, thermal energy disrupts this alignment, causing the material to lose its ferromagnetic properties and transition to a paramagnetic state. This statement is **correct**.

### Step 2: Analyze Option B
**Statement:** "Ferrimagnetic substances do not lose ferrimagnetism on heating and remain ferrimagnetic."

- **Explanation:** Ferrimagnetic substances have unequal magnetic moments that result in a net magnetic moment. However, like ferromagnetic substances, ferrimagnetic substances also lose their magnetic properties when heated sufficiently, transitioning to a paramagnetic state. Thus, this statement is **false**.

### Step 3: Analyze Option C
**Statement:** "Antiferromagnetic substances have domain structures similar to ferromagnetic substances and their magnetic moments are not cancelled by each other."

- **Explanation:** Antiferromagnetic substances have a unique arrangement where adjacent magnetic moments are aligned in opposite directions, effectively canceling each other out. While they may have a domain structure, the magnetic moments do cancel each other, making this statement **false**.

### Step 4: Analyze Option D
**Statement:** "In ferromagnetic substances, all the domains get oriented in the direction of the magnetic field and remain as such even after removing the magnetic field."

- **Explanation:** In ferromagnetic materials, when an external magnetic field is applied, the magnetic domains align in the direction of the field. Even after the removal of the magnetic field, many of these domains remain aligned, giving the material permanent magnetism. This statement is **correct**.

### Conclusion
Based on the analysis:
- **Correct Statements:** Option A and Option D.
- **Incorrect Statements:** Option B and Option C.

### Final Answer
The correct statements are **A and D**.

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