4f spin driven ferroelectric-ferromagnetic multiferroicity in PrMn2 O5 under a magnetic field

Abstract

"In contrast to all other members of the R Mn 2 O 5 family with nonzero 4 f electrons ( R = Nd to Lu), PrMn 2 O 5 does not show any spin driven ferroelectricity in the magnetically ordered phase. By means of high-field electric polarization measurements up to 45 T, we have found that this exceptional candidate undergoes a spin driven multiferroic phase under magnetic field. X-ray magnetic circular dichroism studies up to 30 T at the Pr L 2 edge show that this ferroelectricity originates from and directly couples to the ferromagnetic component of the Pr3+ spins. Experimental observations along with our generalized gradient-approximation +U calculations reveal that this exotic ferroelectric-ferromagnetic combination stabilizes through the exchange-striction mechanism solely driven by a 3 d − 4 f -type coupling, as opposed to the other R Mn 2 O 5 members with 3 d − 3 d driven ferroelectric-antiferromagnetic-type conventional type-II multiferroicity. "