Gigantic magnetoelectric effect caused by magnetic-field-induced canted antiferromagnetic-paramagnetic transition in quasi-two-dimensional Ca${}_2$CoSi${}_2$O${}_7$ crystal

Abstract

We have investigated the magnetic and dielectric properties of Ca${}_2$CoSi${}_2$O${}_7$ crystal. The dielectricity and magnetism of Ca${}_2$CoSi${}_2$O${}_7$ are strongly coupled below a canted antiferromagnetic transition temperature ($T_{\mathrm{N}}$): Magnetic fields induce electric polarization below $T_{\mathrm{N}}$. Interestingly, the magnetic-field-induced electric polarization is detected even without poling electric fields. Below $T_{\mathrm{N}}$, a canted antiferromagnetic-paramagnetic transition is induced by magnetic fields. The large magnetocapacitance is observed around $T_{\mathrm{N}}$. The origin of the large magnetocapacitance is due to the magnetic-field-induced the canted antiferromagnetic-paramagnetic transition.

3 pages, 3 figures. accepted to Applied Physics Letters