title: Understanding the multiferroicity in TmMn2O5by a magnetically induced ferrielectric model.
abstract: The magnetically induced electric polarization behaviors in multiferroic TmMn2O5in response to varying temperature and magnetic field are carefully investigated by means of a series of characterizations including the high precision pyroelectric current technique. Here polycrystalline rather than single crystal samples are used for avoiding the strong electrically self-polarized effect in single crystals, and various parallel experiments on excluding the thermally excited current contributions are performed. The temperature-dependent electric polarization flop as a major character is identified for different measuring paths. The magneto-current measurements indicate that the electric polarization in the low temperature magnetic phase region has different origin from that in the high temperature magnetic phase. It is suggested that the electric polarization does have multiple components which align along different orientations, including the Mn3+-Mn4+-Mn3+exchange striction induced polarization PMM, the Tm3+-Mn4+-Tm3+exchange striction induced polarization PTM, and the low temperature polarization PLTprobably associated with the Tm3+commensurate phase. The observed electric polarization flop can be reasonably explained by the ferrielectric model proposed earlier for DyMn2O5, where PMMand PTMare the two antiparallel components both along the b-axis and PLTmay align along the a-axis. Finally, several issues on the unusual temperature dependence of ferroelectric polarizations are discussed.
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.affiliation: Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.affiliation: Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
authors.forename: M F
authors.initials: MF
authors.lastname: Liu
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.
authors.forename: P L
authors.initials: PL
authors.lastname: Li
authors.affiliation: Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
authors.forename: Z B
authors.initials: ZB
authors.lastname: Yan
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.
authors.forename: M
authors.initials: M
authors.lastname: Zeng
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.
authors.forename: M H
authors.initials: MH
authors.lastname: Qin
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.
authors.forename: X S
authors.initials: XS
authors.lastname: Gao
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.|Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.|Institute for Advanced Materials, Hubei Normal University, Huangshi 435003, China.
authors.forename: J-M
authors.initials: JM
authors.lastname: Liu