Question
In a cassette player, material used for coating magnetic tapes is:

Answer

In cassette player, materials used for magnetic tapes is $NiFe_2​O_4​.$ Ferrites $($Ferromagnetic material$)$ is used for Coating magnetic tapes.
In cassette player or for building memory store in modern computers.
Most common ones are $\ce{MnFe_2​O_4, FeFe_2​O_4​, NiFe_2​O_4}$​ etc.

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