title: Realization of giant magnetoelectricity in helimagnets.
abstract: We show that low field magnetoelectric (ME) properties of helimagnets Ba0.5Sr1.5Zn2(Fe1-xAlx)12O22 can be efficiently tailored by the Al-substitution level. As x increases, the critical magnetic field for switching electric polarization is systematically reduced from approximately 1 T down to approximately 1 mT, and the ME susceptibility is greatly enhanced to reach a giant value of 2.0x10{4} ps/m at an optimum x=0.08. We find that control of the nontrivial orbital moment in the octahedral Fe sites through the Al substitution is crucial for fine-tuning the magnetic anisotropy and obtaining the conspicuously improved ME characteristics.
authors.affiliation: FPRD, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, South Korea.
authors.forename: Sae Hwan
authors.initials: SH
authors.lastname: Chun
authors.forename: Yi Sheng
authors.initials: YS
authors.lastname: Chai
authors.forename: Yoon Seok
authors.initials: YS
authors.lastname: Oh
authors.forename: Deepshikha
authors.initials: D
authors.lastname: Jaiswal-Nagar
authors.forename: So Young
authors.initials: SY
authors.lastname: Haam
authors.forename: Ingyu
authors.initials: I
authors.lastname: Kim
authors.forename: Bumsung
authors.initials: B
authors.lastname: Lee
authors.forename: Dong Hak
authors.initials: DH
authors.lastname: Nam
authors.forename: Kyung-Tae
authors.initials: KT
authors.lastname: Ko
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Park
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Chung
authors.forename: Kee Hoon
authors.initials: KH
authors.lastname: Kim