title: Near-field evidence for ferromagnetic "nanoneedles" in Nd1/2Sr1/2MnO3.
abstract: We report on the near-field optical microscopic (NSOM) imaging of single-crystal Nd1/2Sr1/2MnO3 near the first-order phase transition from the CE-type charge-ordered insulator (COI) to the ferromagnetic metal (FMM) at 165 K. Using polarized light, the measurements are sensitive to twin domains through optical anisotropy and to hysteretic inhomogeneous strain associated with the phase transition. Optical evidence for strain relaxation and multiphase coexistence is observed through the transition from 150 to 165 K. The multiphase coexistence is seen as the formation of FMM "nanoneedles" with widths less than 100 nm and lengths of at least several micrometers at temperatures well below TC. The work demonstrates polarized NSOM as a technique for the study of first-order solid-state phase transformations on the nanometer spatial scale.
authors.affiliation: Laboratory for Physical Sciences, University of Maryland, College Park, Maryland 20740, USA. pkolb@lps.umd.edu
authors.forename: Paul W
authors.initials: PW
authors.lastname: Kolb
authors.forename: Danilo B
authors.initials: DB
authors.lastname: Romero
authors.forename: H Dennis
authors.initials: HD
authors.lastname: Drew
authors.forename: Andrei B
authors.initials: AB
authors.lastname: Sushkov
authors.forename: Satish B
authors.initials: SB
authors.lastname: Ogale
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Moritomo
mesh_terms: D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008280:Magnetics; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances