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

摘要

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