Question

Ferrimagnetism is in:
A. $\uparrow \uparrow \uparrow \uparrow \uparrow$
B. $\uparrow \downarrow \uparrow \downarrow$
C. $\uparrow \uparrow \uparrow \downarrow \downarrow$
D. $\uparrow \uparrow \downarrow \downarrow \uparrow \uparrow \uparrow \downarrow \downarrow \downarrow$

Answer 1

Magnetism is a phenomenon exhibited by substances having properties to attract or repel each other under the presence of electric and magnetic fields.

Complete step by step answer: Under the presence of an external magnetic field the atoms in a substance align themselves in opposite spins. Some of them align in parallel and some in antiparallel spin. The numbers of atoms which align in opposite magnetic moments give rise to three different types of magnetic substances.
The three types of substances are called ferromagnetic, antiferromagnetic and ferrimagnetic substances. The corresponding magnetic properties exhibited by these substances are termed as ferromagnetism, antiferromagnetism and ferrimagnetism.
The substances showing ferromagnetism have the atoms oriented in the same direction. The substances showing antiferromagnetism have the equal number of atoms oriented in opposite directions. The substances showing ferrimagnetism have an unequal number of atoms in opposite directions.
Let us check the given set of options to identify which pair of atoms shows ferrimagnetism.
A. $\uparrow \uparrow \uparrow \uparrow \uparrow$. In this case it is seen that all the atoms are in parallel spins. So it exhibits ferromagnetism.
B. $\uparrow \downarrow \uparrow \downarrow$ . In this case it is seen that two atoms are in parallel and two are in anti parallel spins. As the number of parallel and antiparallel spins of atoms are equal so the substance will exhibit antiferromagnetism.
C. $\uparrow \uparrow \uparrow \downarrow \downarrow$ . In this case it is seen that three atoms are in parallel and two atoms are in antiparallel spins. As the number of parallel and antiparallel spins of atoms are unequal so the substance will exhibit ferrimagnetism.
D. $\uparrow \uparrow \downarrow \downarrow \uparrow \uparrow \uparrow \downarrow \downarrow \downarrow$ . In this case it is seen that five atoms are in parallel and five are in anti parallel spins. As the number of parallel and antiparallel spins of atoms are equal so the substance will exhibit antiferromagnetism.
Hence option C is the correct answer.

Note: Ferrimagnetism should not be confused with antiferromagnetism as both involve atoms with opposite spins. Ferrimagnetism seems to be a combination of ferromagnetism and antiferromagnetism but it is unique in its magnetic property.