Magnetocapacitance effect and magnetoelectric coupling in type-II multiferroic HoFeWO6

We have investigated the multiferroicity and magnetoelectric (ME) coupling in HoFeWO6. With a noncentrosymmetric polar structure (space group Pna2(1)) at room temperature, this compound shows an onset of electric polarization with an antiferromagnetic ordering at the Neel temperature (T-N) of 17.8 K. The magnetic properties of the polycrystalline samples were studied by DC and AC magnetization and heat capacity measurements. The metamagnetic behavior at low temperatures was found to be directly related to the dielectric properties of the compound. In particular, field-dependent measurements of capacitance show a magnetocapacitance (MC) effect with double-hysteresis loop behavior in direct correspondence with the magnetization. Our x-ray diffraction results show the Pna2(1) structure down to 8 K and suggest the absence of a structural phase transition across TN. Soft x-ray absorption spectroscopy and soft x-ray magnetic circular dichroism (XMCD) measurements at the Fe L-2,L-3 and Ho M-4,M-5 edges revealed the oxidation state of Fe and Ho cations to be 3+. Fe L-2,L-3 XMCD further shows that Fe3+ cations are antiferromagnetically ordered in a noncollinear fashion with spins arranged 90 degrees with respect to each other. Our findings show that HoFeWO6 is a type-II multiferroic exhibiting a MC effect. The observed MC effect and the change in polarization by the magnetic field, as well as their direct correspondence with magnetization, further support the strong ME coupling in this compound.

Automated summary

HoFeWO6 exhibits multiferroicity and magnetoelectric (ME) coupling, with electric polarization onset at 17.8 K and antiferromagnetic ordering. The compound shows metamagnetic behavior at low temperatures directly related to dielectric properties, with a magnetocapacitance (MC) effect observed. X-ray diffraction results confirm the noncentrosymmetric polar structure and suggest Fe3+ cations are antiferromagnetically ordered in a noncollinear fashion. The observed MC effect, change in polarization by magnetic field, and direct correspondence with magnetization support strong ME coupling in HoFeWO6.