Giant Room‐Temperature Magnetodielectric Response in a MOF at 0.1 Tesla

A giant room‐temperature magnetodielectric (MD) response upon the application of a small magnetic field is of fundamental importance for the practical application of a new generation of devices. Here, the giant room‐temperature magnetodielectric response is demonstrated in the metal–organic framework (MOF) of [NH 2 (CH 3 ) 2 ] n [Fe III Fe II (1− x ) Ni II x (HCOO) 6 ] n ( x ≈ 0.63–0.69) ( 1) with its MD coefficient remaining between −20% and −24% in the 300–410 K temperature range, even at 0.1 T. Because a room‐temperature magnetodielectric response has never been observed in MOFs, the present work not only provides a new type of magnetodielectric material but also takes a solid step toward the practical application of MOFs in a new generation of devices.