Ferromagnetic resonance at 9.5 GHz was performed on ferrimagnetic nano-crystalline Zn-ferrite thin films deposited under different preparation conditions. A very low line width of 40 Oe was observed ...in as-sputtered 100 W thin films in perpendicular configuration. The pulsed laser deposited films show comparatively higher line widths. This work shows that it is possible to deposit ferrite thin films with low line width and good magnetization values without going through a high temperature processing.
•Lead-free NKBT ceramics were synthesized by solid-state sintering method.•NKBT exhibited highest Pr ∼ 40 μC/cm2 and low coercive field, EC ∼ 30 kV/cm.•Maximum d33 and kp of 193 pC/N and 54 % was ...achieved for EP =50 kV/cm at RT.•Broad Raman bands with reduced FWHM in poled ceramic displayed long range ferroelectric domain ordering.•Highest g33 (85.6 mV.m/N) and d33* ∼ 715 pm/V were obtained at TP =110 °C, EP =50 kV/cm.
The effect of electric poling on the piezoelectric properties of the sintered Na0.4K0.1Bi0.5TiO3 is studied with varying poling field and temperature. An optimized poling condition (EP =50 kVcm, TP =110 °C) exhibited a high piezoelectric voltage (g33∼ 85 mV m/N) and charge coefficients (d33∼193pC/N). A combination of electric field induced irreversible transformation from polar nano regions embedded in a non-polar relaxor state to a long-range ordered ferroelectric state and increase in the structural ordering are responsible for the observed high piezoelectric properties. A mechanism is discussed to reveal the origin of high voltage coefficient due to poling, where the decrease of dielectric permittivity can facilitate high g33. This investigation provides an approach for designing the high performance Na0.4K0.1Bi0.5TiO3based materials suitable for sensors and energy harvesting applications.
Yttrium-iron-garnet (YIG) thin films were grown on quartz substrates using pulsed laser deposition (PLD) while varying oxygen gas pressure (P O2 ) in the range of 6.5 × 10 -3 mbar to 1 mbar. YIG ...phase formation and magnetic properties were strongly dependent on P O2 . The YIG thin film grown at 1.7 × 10 -1 mbar shows the best magnetic properties (4π M s ≈ 1650 G, low H C ≈ 2 Oe) and FMR linewidth (ΔH ≈ 60 Oe) compared to films grown at other P O2 . Our results show that it is possible to obtain single-phase YIG films with low H C and ΔH even on quartz substrates by adjusting the P O2 during deposition.
A significant advance in the understanding of grain boundary contribution to magnetization in nanocrystalline ferrite thin films is demonstrated in this paper. RF-sputtered, ...room-temperature-deposited lithium–zinc ferrite thin films (Li
0.5−
x
/2Zn
x
Mn
0.1Fe
2.35−
x
/2O
4, with
x=0.0, 0.16, 0.32 and 0.48) have been thermally annealed ex-situ at 850
°C and the in-plane magnetic measurements have been performed using a vibrating sample magnetometer. The percentage deviation between bulk and film magnetization (
δ
M
) is observed to decrease with increasing Zn concentration, till
x=0.32, and then it increases. Macro-texture measurements using X-ray orientation distribution function and micro-texture measurements using orientation imaging microscopy show reverse trend in the extent of crystallographic texturing and in the computed fraction of low-angle grain boundaries. This study brings out a correlation between low-angle grain boundary concentration and
δ
M
.
Magnetic and FMR Study on CoFe2O4/ZnFe2O4 Bilayers Sahu, B. N.; Sahoo, S. C.; Venkataramani, N. ...
IEEE transactions on magnetics,
07/2013, Letnik:
49, Številka:
7
Journal Article, Conference Proceeding
CoFe 2 O 4 /ZnFe 2 O 4 bilayers were deposited by the pulsed laser deposition on amorphous fused quartz substrate at substrate temperature of 350°C and in oxygen pressure of 0.16 mbar. The films were ...studied after ex-situ annealing for 2 h in air at various temperatures up to 650°C. The magnetic properties of the bilayers were studied at 300 K and at 10 K. Ferromagnetic resonance was carried out at x-band frequencies at room temperature. It was found that as a result of annealing, the diffusion between Co ferrite and Zn ferrite starts around 350°C and leads to a large line width system having magnetization, which remains undetected by Ferromagnetic resonance.
Nanocrystalline spinel CoFe
2
O
4
/ZnFe
2
O
4
bilayers were deposited by the pulsed laser deposition technique on amorphous fused quartz substrate at different substrate temperatures ranging from ...room temperature to 750 °C. The magnetic properties of the bilayers and of the single layer films deposited in identical conditions were studied at 300 K and at 10 K. Magnetic properties of the bilayers, in general, were found to be in between the individual values of the single layers. Magnetic measurements at 10 K clearly showed a two stepped magnetic hysteresis loop corresponding to the switching of the magnetic moments of the soft ZnFe
2
O
4
and the hard CoFe
2
O
4
layers. A study was also carried out by changing the thickness of ZnFe
2
O
4
layer in the bilayer. This study showed that the magnetic properties of the bilayers even at room temperature can be controlled to some extent by changing the thickness of the soft ZnFe
2
O
4
layer while maintaining a low substrate temperature of 350 °C.
CoFeFormula OmittedOFormula Omitted/ZnFeFormula OmittedOFormula Omitted bilayers were deposited by the pulsed laser deposition on amorphous fused quartz substrate at substrate temperature of ...350Formula OmittedC and in oxygen pressure of 0.16 mbar. The films were studied after ex-situ annealing for 2 h in air at various temperatures up to 650Formula OmittedC. The magnetic properties of the bilayers were studied at 300 K and at 10 K. Ferromagnetic resonance was carried out at x-band frequencies at room temperature. It was found that as a result of annealing, the diffusion between Co ferrite and Zn ferrite starts around 350Formula OmittedC and leads to a large line width system having magnetization, which remains undetected by Ferromagnetic resonance.
Different strategies for tuning the properties of ferroelectric materials have been employed for advancing electromechanical applications. Among several material synthesis techniques explored, site ...substitution is an effective approach. The present work focuses on Ba1-xCaxSnyTi1-yO3 (BCST) ceramics prepared by solid-state sintering route with different substitution levels (x = 0, 0.05 and y = 0, 0.09). The impact of site substitution on the properties of Barium Titanate (BTO), phase purity, structural analysis, chemical composition, dielectric, and ferroelectric properties have been studied. An ionic radii difference at A-site and B-site substitution is a key factor to achieve significant changes in physical and structural properties. X-ray diffraction patterns ensure the formation of pure phase perovskite structure in all the compositions. Raman spectroscopy indicates Ca substitution not only occurs at the A-site but also within the oxygen octahedra, adversely affecting the properties. Ca and Sn act as strong grain growth inhibitors, leading to a fine-grained and dense microstructure in BCST. While Ca substitution has a limited impact on the Curie temperature (TC), Sn substitution lowers TC in BST (54 °C) and BCST (50 °C) compared to BTO (126 °C). The Sn substitution results in the coexistence of multiple phases (rhombohedral, tetragonal and orthorhombic) in BST, enhancing its properties (ε' = 6118 at RT, Pr = 5.50 μC/cm2, Q11 = 0.060 m4/C2, d*33 = 526 pm/V) in comparison to BTO. These results acknowledge the role of substituents in lattice disruption, paving the way for chemistry-based materials design in the field of dielectric, actuator and energy storage applications.
•Ca and Sn are substituted simultaneously at Ba and Ti sites in BaTiO3 ceramic, respectively.•Raman spectroscopy, Rietveld refinement and dielectric measurement confirm a minute Ca substitution at Ti site in BaTiO3.•In comparison to BaTiO3, the Sn enhances the electrical properties, while Ca deteriorates the same.•Multiphase coexistence accounts for improved electrical properties in BaSn0.09Ti0.91O3 and Ba0.95Ca0.05Sn0.09Ti0.91O3.
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•Pb-free Na0.4K0.1Bi0.5TiO3 thin film with 100-preferential orientation is grown by the Pulsed Laser Deposition technique.•The texture of the film is controlled by varying substrate ...temperatures (600-750°C).•Low dielectric loss (≈ 0.08 at 1kHz), high remnant polarization (≈17.8 µC/cm2), and effective piezoelectric coefficient (≈76 pm/V) are availed for the textured film.
Pb-free ferroelectric thin films are gaining attention due to their applicability in memory, sensor, actuator, and microelectromechanical system. In this work, Na0.4K0.1Bi0.5TiO3 (NKBT0.1) ferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si substrates using the pulsed laser deposition (PLD) technique at various substrate temperatures (600–750 °C). The comprehensive structural, microstructural, and ferroelectric properties characterizations depicted the effect of substrate temperature on the grain size, dielectric constant, and remnant polarization of the films. The influence of higher substrate temperatures on the control of 100-preferential orientations was observed. Significantly, films deposited at 700 °C exhibited reduced dielectric loss of ∼0.13 (at 100 kHz), a high dielectric constant of ∼ 506 (at 100 kHz), and remnant polarization of ∼17 µC/cm2. At this deposition temperature, the maximum effective piezoelectric coefficient (d33*) of ≈ 76 pm/V was availed. Based on the structural analysis, dielectric properties, and ferroelectric behavior, the optimal deposition temperature for the NKBT0.1 thin films was determined to be 700 °C. This study contributes to the understanding of the influence of substrate temperature on the structural and ferroelectric properties of Pb-free NKBT0.1 thin films, providing insights into the development of high-performance ferroelectric devices.
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