Electro-optic switching in iron oxide nanoparticle embedded paramagnetic chiral liquid crystal via magneto-electric coupling

Journal Article · Fri Mar 28 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4869740· OSTI ID:22271316

Goel, Puja ^[1]; Arora, Manju; Biradar, Ashok M. ^[2]

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1. Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi 110012 (India)
2. Materials Physics and Engineering Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India)

The variation in optical texture, electro-optic, and dielectric properties of iron oxide nanoparticles (NPs) embedded ferroelectric liquid crystal (FLC) with respect to change in temperature and electrical bias conditions are demonstrated in the current investigations. Improvement in spontaneous polarization and response time in nanocomposites has been attributed to magneto-electric (ME) coupling resulting from the strong interaction among the ferromagnetic nanoparticle's exchange field (due to unpaired e{sup −}) and the field of liquid crystal molecular director. Electron paramagnetic resonance spectrum of FLC material gives a broad resonance signal with superimposed components indicating the presence of a source of spin. This paramagnetic behavior of host FLC material had been a major factor in strengthening the guest host interaction by giving an additional possibility of (a) spin-spin interaction and (b) interactions between magnetic-dipole and electric-dipole moments (ME effects) in the composite materials. Furthermore, the phenomenon of dielectric and static memory effect in these composites are also observed which yet again confirms the coupling of magnetic NP's field with FLC's director orientation. We therefore believe that such advanced soft materials holding the optical and electrical properties of conventional LCs with the magnetic and electronic properties of ferromagnetic nanoparticles are going to play a key role in the development of futuristic multifunctional optical devices.

• OSTI ID: 22271316
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 12; 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
ABSORPTION SPECTRA
CHIRALITY
COMPOSITE MATERIALS
DIELECTRIC PROPERTIES
ELECTRIC DIPOLE MOMENTS
ELECTRON SPIN RESONANCE
FERROELECTRIC MATERIALS
IRON OXIDES
J-J COUPLING
LIQUID CRYSTALS
MAGNETIC DIPOLES
NANOSTRUCTURES
PARAMAGNETISM
PARTICLES
POLARIZATION
SPIN
TEXTURE