Physical properties of bifunctional BST/LSMO nanocomposites

Journal Article · Fri Feb 28 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4866555· OSTI ID:22278018

Beltran-Huarac, Juan; Morell, Gerardo ^[1]; Martinez, Ricardo ^[2]

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1. Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931 (United States)
2. Department of Mathematics and Physics, University of Puerto Rico, Cayey Campus, Cayey, Puerto Rico 00737 (United States)

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 analysis of the MC{sub p} measurements indicates that one of the BST/LSMO compositions studied can be considered as a new multiferroic compound.

• OSTI ID: 22278018
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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