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Title: Physical properties of bifunctional BST/LSMO nanocomposites

We report the fabrication of bifunctional nanocomposites consisting of ferroelectric Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} (BST) and ferromagnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) at different concentrations via a high-temperature solid state route. The structural, dielectric, electrical, magnetodielectric (MD), magnetoelectric (ME) and magnetic properties of BST/LSMO nanocomposites were systematically investigated over a wide range of temperatures and frequencies. The X-Ray Diffraction analyses reveal the nanocrystalline nature of the heterostructures, wherein both perovskite phases co-exist. No parasitic phases were observed. The study of the dielectric properties shows that the nanocomposites exhibit relaxor ferroelectric character, with ferroelectric-paraelectric phase transition temperatures around 287–292 K that do not follow the Curie-Weiss law. The electrical measurements indicate that ac conductivities of the nanocomposites follow the Jonscher's universal power law, with activation energies of 0.42–0.63 eV based on Arrhenius-type behavior at high temperatures. The nanocomposites exhibit well-defined ferromagnetic hysteresis loops at room temperature (RT). The MD and ME measurements at RT indicate that BST/LSMO exhibits a nonlinear ME effect at low frequencies, with a threshold near 0.5 T. The magnetocapacitance (MC{sub p}) measurements evidence a quadratic dependence on magnetic field, further confirming the multiferroic nature of BST/LSMO. The order of MC{sub p} was found to be ∼7% per Tesla. The analysismore » of the MC{sub p} measurements indicates that one of the BST/LSMO compositions studied can be considered as a new multiferroic compound.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931 (United States)
  2. (United States)
  3. Department of Mathematics and Physics, University of Puerto Rico, Cayey Campus, Cayey, Puerto Rico 00737 (United States)
Publication Date:
OSTI Identifier:
22278018
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ACTIVATION ENERGY; BARIUM COMPOUNDS; COMPOSITE MATERIALS; CRYSTALS; CURIE-WEISS LAW; DIELECTRIC PROPERTIES; FABRICATION; FERROELECTRIC MATERIALS; FERROMAGNETIC MATERIALS; HYSTERESIS; MAGNETIC FIELDS; MAGNETIC PROPERTIES; NANOSTRUCTURES; NONLINEAR PROBLEMS; PHASE TRANSFORMATIONS; SOLIDS; STRONTIUM TITANATES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; TRANSITION TEMPERATURE