Room temperature p-type conductivity and coexistence of ferroelectric order in ferromagnetic Li doped ZnO nanoparticles

Journal Article · Tue Oct 28 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4900413· OSTI ID:22308177

Hasanain, S. K. ^[1]; Anjum, D. H. ^[2]; Awan, M. S. ^[3]; Shah, Saqlain A. ^[4]

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1. Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
2. Advanced Nanofabrication, Imaging and Characterization Core Lab (ANIC), King Abdullah University of Science and Technology (KAUST), Thuwal, Makkah 23599-6900 (Saudi Arabia)
3. Center for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)
4. Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States)

Memory and switching devices acquired new materials which exhibit ferroelectric and ferromagnetic order simultaneously. We reported multiferroic behavior in Zn{sub 1−y}Li{sub y}O(0.00≤y≤0.10) nanoparticles. The analysis of transmission electron micrographs confirmed the hexagonal morphology and wurtzite crystalline structure. We investigated p-type conductivity in doped samples and measured hole carriers in range 2.4 × 10{sup 17}/cc to 7.3 × 10{sup 17}/cc for different Li contents. We found that hole carriers are responsible for long range order ferromagnetic coupling in Li doped samples. Room temperature ferroelectric hysteresis loops were observed in 8% and 10% Li doped samples. We demonstrated ferroelectric coercivity (remnant polarization) 2.5 kV/cm (0.11 μC/cm{sup 2}) and 2.8 kV/cm (0.15 μC/cm{sup 2}) for y = 0.08 and y = 0.10 samples. We propose that the mechanism of Li induced ferroelectricity in ZnO is due to indirect dipole interaction via hole carriers. We investigated that if the sample has hole carriers ≥5.3 × 10{sup 17}/cc, they can mediate the ferroelectricity. Ferroelectric and ferromagnetic measurements showed that higher electric polarization and larger magnetic moment is attained when the hole concentration is larger and vice versa. Our results confirmed the hole dependent coexistence of ferromagnetic and ferroelectric behavior at room temperature, which provide potential applications for switchable and memory devices.

• OSTI ID: 22308177
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 16 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CARRIERS
COERCIVE FORCE
COUPLING
DIPOLES
DOPED MATERIALS
EQUIPMENT
FERROELECTRIC MATERIALS
HOLES
HYSTERESIS
INTERACTIONS
LITHIUM ADDITIONS
MAGNETIC MOMENTS
MEMORY DEVICES
NANOPARTICLES
POLARIZATION
TEMPERATURE RANGE 0273-0400 K
TRANSMISSION
ZINC OXIDES