title: Hollandites as a new class of multiferroics.
abstract: Discovery of new complex oxides that exhibit both magnetic and ferroelectric properties is of great interest for the design of functional magnetoelectrics, in which research is driven by the technologically exciting prospect of controlling charges by magnetic fields and spins by applied voltages, for sensors, 4-state logic, and spintronics. Motivated by the notion of a tool-kit for complex oxide design, we developed a chemical synthesis strategy for single-phase multifunctional lattices. Here, we introduce a new class of multiferroic hollandite Ba-Mn-Ti oxides not apparent in nature. BaMn3Ti4O14.25, designated BMT-134, possesses the signature channel-like hollandite structure, contains Mn(4+) and Mn(3+) in a 1:1 ratio, exhibits an antiferromagnetic phase transition (TN ~ 120 K) with a weak ferromagnetic ordering at lower temperatures, ferroelectricity, a giant dielectric constant at low frequency and a stable intrinsic dielectric constant of ~200 (1-100 MHz). With evidence of correlated antiferromagnetic and ferroelectric order, the findings point to an unexplored family of structures belonging to the hollandite supergroup with multifunctional properties, and high potential for developing new magnetoelectric materials.
authors.affiliation: 1] Department of Chemistry, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA [2] The CUNY Energy Institute, City University of New York, Steinman Hall, 160 Convent Avenue, The City College of New York, New York, NY 10031, USA.
authors.forename: Shuangyi
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Materials Science &Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Akbashev
authors.affiliation: Department of Applied Physics and Applied Mathematics, The Fu Foundation School of Engineering and Applied Science, Columbia University, Mudd Building, 500 West 120th Street, New York, NY 10027, USA.
authors.forename: Xiaohao
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Chemistry, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Chemistry, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA.
authors.forename: Wanlu
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Physics, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA.
authors.forename: Lukas
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Chemical Engineering, The Grove School of Engineering, Steinman Hall, 160 Convent Avenue, The City College of New York, New York, NY 10031, USA.
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.affiliation: 1] Department of Chemical Engineering, The Grove School of Engineering, Steinman Hall, 160 Convent Avenue, The City College of New York, New York, NY 10031, USA [2] The CUNY Energy Institute, City University of New York, Steinman Hall, 160 Convent Avenue, The City College of New York, New York, NY 10031, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Couzis
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Myung-Geun
authors.initials: MG
authors.lastname: Han
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Yimei
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Physics, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA.
authors.forename: Lia
authors.initials: L
authors.lastname: Krusin-Elbaum
authors.affiliation: Department of Mechanical Engineering, The Grove School of Engineering, Steinman Hall, 160 Convent Avenue, The City College of New York, New York, NY 10031, USA.
authors.forename: Jackie
authors.initials: J
authors.lastname: Li
authors.affiliation: 1] Department of Chemistry, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA [2] Department of Chemistry, South University of Science and Technology of China, Shenzhen 518500, P. R. China.
authors.forename: Limin
authors.initials: L
authors.lastname: Huang
authors.affiliation: 1] Department of Applied Physics and Applied Mathematics, The Fu Foundation School of Engineering and Applied Science, Columbia University, Mudd Building, 500 West 120th Street, New York, NY 10027, USA [2] Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Simon J L
authors.initials: SJ
authors.lastname: Billinge
authors.affiliation: 1] Department of Materials Science &Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA [2] A J Drexel Institute for Energy &the Environment, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Spanier
authors.affiliation: 1] Department of Chemistry, The City College of New York, Marshak Building, 160 Convent Avenue, NY 10031, USA [2] The CUNY Energy Institute, City University of New York, Steinman Hall, 160 Convent Avenue, The City College of New York, New York, NY 10031, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: O'Brien