Magnetic Properties and Magnetodielectric Effect in (C6H5CH2NH3)2[CuCl4] with Organic-Inorganic Hybrid Layered Structure

Abstract

Metal Organic Frameworks (MOFs) are a group of multiferroic candidates that exhibit various optical, electrical, magnetic, and structural properties depending on the type of organic cations, transition metals and halogen elements, and their molar ratio. (C6H5CH2NH3)2[CuCl4] (BZACC), one of the MOF materials, has a special hybrid layered structure of organic and inorganic layers. Magnetic property measurement showed that BZACC exhibits weak in-plane ferromagnetism below the Curie point (TC) of 10.25 K and the saturated magnetic moment of 1 µB per formula unit at 2 K. When the magnetic field is less than 0.1 T along the c axis, it exhibits weak antiferromagnetism below 8 K. From the measurement of the dielectric constant with external magnetic field, we observed a maximum magnetodielectric (MD) effect of 0.4% at 2 K. Furthermore, it was found that the magnetic-field dependence of the MD effect is similar to that of the second derivative of magnetization with respect to magnetic field. We suggest that the observed MD effect is the consequence of the magnetic-field-induced spin structure change in the inorganic layer, which induces the change in the interlayer magnetic coupling and, as a result, induces the change in the dielectric constant by the applied magnetic field.