Gigantic magnetoelectric effect caused by magnetic-field-induced canted antiferromagnetic-paramagnetic transition in quasi-two-dimensional Ca_2CoSi_2O_7 crystal

摘要

We have investigated the magnetic and dielectric properties of Ca_2CoSi_2O_7 crystal. The dielectricity and magnetism of Ca_2CoSi_2O_7 are strongly coupled below a canted antiferromagnetic transition temperature (T_N). Magnetic fields induce electric polarization below T_N. Interestingly, the magnetic-field-induced electric polarization is detected even without poling electric fields. Below T_N, a canted antiferromagnetic-paramagnetic transition is induced by magnetic fields. The large magnetocapacitance is observed around T_N. The origin of the large magnetocapacitance is due to the magnetic-field-induced the canted antiferromagnetic-paramagnetic transition.