title: Spontaneous liquid crystal and ferromagnetic ordering of colloidal magnetic nanoplates.
abstract: Ferrofluids are familiar as colloidal suspensions of ferromagnetic nanoparticles in aqueous or organic solvents. The dispersed particles are randomly oriented but their moments become aligned if a magnetic field is applied, producing a variety of exotic and useful magnetomechanical effects. A longstanding interest and challenge has been to make such suspensions macroscopically ferromagnetic, that is having uniform magnetic alignment in the absence of a field. Here we report a fluid suspension of magnetic nanoplates that spontaneously aligns into an equilibrium nematic liquid crystal phase that is also macroscopically ferromagnetic. Its zero-field magnetization produces distinctive magnetic self-interaction effects, including liquid crystal textures of fluid block domains arranged in closed flux loops, and makes this phase highly sensitive, with it dramatically changing shape even in the Earth's magnetic field.
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: M
authors.initials: M
authors.lastname: Shuai
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: A
authors.initials: A
authors.lastname: Klittnick
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: G P
authors.initials: GP
authors.lastname: Smith
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Tuchband
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: C
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: Petschek
authors.affiliation: Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia.
authors.forename: A
authors.initials: A
authors.lastname: Mertelj
authors.affiliation: Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia.
authors.forename: D
authors.initials: D
authors.lastname: Lisjak
authors.affiliation: Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia.|Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Čopič
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Maclennan
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Glaser
authors.affiliation: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Clark
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