Which of the following arrangements shows schematic alignment of magnetic moments of antiferromagnetic substances?

Options

A.
B.
C.
D.

Explanation

To determine the schematic alignment of magnetic moments in antiferromagnetic substances, we need to analyze the given options based on the characteristics of antiferromagnetism.

### Step-by-Step Solution:

1. **Understanding Antiferromagnetism**:
- Antiferromagnetic substances have magnetic moments that align in opposite directions. This means that for every magnetic moment pointing in one direction, there is another pointing in the opposite direction. This results in a net magnetic moment of zero.

2. **Analyzing the Options**:
- **Option A**: If the arrangement shows all magnetic moments pointing in the same direction, this indicates ferromagnetism, not antiferromagnetism.
- **Option B**: Similar to Option A, if all magnetic moments are aligned in the same direction, this is also indicative of ferromagnetism.
- **Option C**: If the arrangement shows magnetic moments that are unequal but still aligned in opposite directions, this may indicate ferrimagnetism, which is different from antiferromagnetism.
- **Option D**: If the arrangement shows alternating magnetic moments, where one is pointing up and the next is pointing down, this is characteristic of antiferromagnetism.

3. **Conclusion**:
- Based on the analysis, the correct option that shows the schematic alignment of magnetic moments of antiferromagnetic substances is **Option D**.

### Final Answer:
- **Option D** is the correct answer as it represents the alternating alignment of magnetic moments characteristic of antiferromagnetic substances.