Kim, JungHwaLee, SeunghunPark, SungilKenzelmann, MichelHarris, A. BrooksSchefer, JürgChung, JaehoMajkrzak, Charles FTakeda, MasayasuWakimoto, ShuichiPark, SoonyongCheong, SangwookMatsuda, MasaakiKimura, HisamichiNoda, YukioKakurai, Kazuhisa2023-05-232023-05-232008-12-192015-08-18https://repository.upenn.edu/handle/20.500.14332/43173By combining neutron four-circle diffraction and polarized neutron-diffraction techniques we have determined the complex spin structures of a multiferroic YMn2O5 that exhibits two ferroelectric phases at low temperatures. The obtained magnetic structure has spiral components in both the low-temperature ferroelectric phases that are magnetically commensurate and incommensurate, respectively. Among proposed microscopic theories for the magnetoelectric coupling, our results are consistent with both the spin-current mechanism and the magnetostriction mechanism. Our results also explain why the electric polarization changes at the low-temperature commensurate-to-incommensurate phase transition.PhysicsArticle