Magnetodielectric coupling of a polar organic-inorganic hybrid Cr(II) phosphonate

Abstract

$\text{Cr}[({\text{H}}_{3}\text{N-}{({\text{CH}}_{2})}_{2}{\text{-PO}}_{3})(\text{Cl})({\text{H}}_{2}\text{O})]$ represents a rare example of a polar organic-inorganic hybrid material that exhibits a canted antiferromagnetic order below ${T}_{N}=5.5\text{ }\text{K}$. The unusual coexistence of a polar crystal structure and magnetic order triggered our investigation of the magnetodielectric coupling. The coupling is evidenced by an anomaly in the temperature dependence of the dielectric constant $\ensuremath{\epsilon}$ below the N\'eel temperature. The magnetocapacitance is enhanced by one order of magnitude below ${T}_{N}$. The main characteristics of the magnetodielectic response are interpreted by Landau theoretical coupling terms.