title: Thermally or magnetically induced polarization reversal in the Multiferroic CoCr2O4.
abstract: We report the unexpected evolution, with thermal and magnetic-field (H) variations, of the interrelation between the polarization P, magnetization M, and spiral wave vector Q in CoCr2O4, which has a ferrimagnetic conical-spiral magnetic order. For example, P suddenly jumps and changes its sign at the magnetic lock-in transition (T_{L}) with thermal variation, or with isothermal variation of H (without changing its direction) at T_{L}, which surprisingly occurs without change in spiral handedness (i.e., the sign of Q). The presence of multiple spiral sublattices may be behind this unusual behavior.
authors.affiliation: Rutgers Center for Emergent Materials and Department of Physics and Astronomy, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Choi
authors.forename: J
authors.initials: J
authors.lastname: Okamoto
authors.forename: D J
authors.initials: DJ
authors.lastname: Huang
authors.forename: K S
authors.initials: KS
authors.lastname: Chao
authors.forename: H J
authors.initials: HJ
authors.lastname: Lin
authors.forename: C T
authors.initials: CT
authors.lastname: Chen
authors.forename: M
authors.initials: M
authors.lastname: van Veenendaal
authors.forename: T A
authors.initials: TA
authors.lastname: Kaplan
authors.forename: S-W
authors.initials: SW
authors.lastname: Cheong