Abstract
The discovery of single-phase multiferroic materials and the
understanding of coupling mechanisms between their spin and polarization
is important from the point of view of next generation logic and memory
devices. Herein we report the fabrication, dielectric, ferroelectric,
piezo-response force microscopy, and magnetization measurements of
Pd-substituted room-temperature magnetoelectric multiferroic PbPd0.3Ti0.7O3 (PbPdT) thin films. Highly oriented PbPdT thin films were deposited on {(LaAlO3)0.3(Sr2AlTaO6)0.7}
(LSAT) substrates in oxygen atmosphere using pulsed laser deposition
technique. X-ray diffraction studies revealed that the films had
tetragonal phase with (001) orientation. Surface morphology studies
using atomic force and scanning electron microscopy suggest a smooth and
homogeneous distribution of grains on the film surface with roughness
~2 nm. A large dielectric constant of ~1700 and a low-loss tangent value
of ~0.3 at 10 kHz were obtained at room temperature. Temperature
dependent dielectric measurements carried out on Pt/PbPdT/La0.7Sr0.3MnO3
(LSMO) metal-dielectric-metal capacitors suggest a ferroelectric to
paraelectric transition above 670 K. The measured polarization
hysteresis loops at room temperature were attributed to its
ferroelectric behavior. From a Tauc plot of (αhν)2 versus energy, the direct band gap Eg
of PbPdT thin films was calculated as 3 eV. Ferroelectric piezoelectric
nature of the films was confirmed from a strong domain switching
response revealed from piezo-response force microscopy. A well-saturated
magnetization M-H loop with remanent magnetization of 3.5 emu/cm3
was observed at room temperature, and it retains ferromagnetic ordering
in the temperature range 5–395 K. Origin of the magnetization could be
traced to the mixed oxidation states of Pd2+/Pd4+ dispersed in polar PbTiO3
matrix, as revealed by our x-ray photoelectron spectroscopic results.
These results suggest that PbPdT thin films are multiferroic
(ferroelectric-ferromagnetic) at room temperature.
Original language | English |
---|---|
Article number | 2991 |
Number of pages | 11 |
Journal | Scientific Reports |
Volume | 10 |
DOIs | |
Publication status | Published - 19 Feb 2020 |