Enhanced Coercivity in BiFeO3/SrRuO3heterostructures

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 597-602 ◽  
Author(s):  
Srinivasa Rao Singamaneni ◽  
J. T. Prater ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Domain Walls ◽  
Dissimilar Materials ◽  
Substrate Material ◽  
Buffer Layers ◽  
Oxide Thin Film ◽  
Magnetic Data ◽  
Piezo Force Microscopy ◽  
Underlying Mechanisms

ABSTRACTTransition metal oxide thin film heterostructures have garnered increasing research interest in the last decade due to their multifunctional properties, such as ferromagnetism and ferroelectricity, which may be utilized in next generation device applications. Many previous works reported on the deposition of such structures on oxide substrates such as SrTiO3, which are not compatible with CMOS applications where Si(100) is the mainstay substrate material. BiFeO3(BFO) is a room temperature insulating ferroelectric and antiferromagnet, a well-known multiferroic material. SrRuO3(SRO) is a ferromagnetic metal with the Curie temperature (TC) of 165K. Unexpected properties emerge when these two dissimilar materials are conjoined. However, there has been no report on exploring the magnetic properties of BFO when it is in contact with SRO, and particularly when they are integrated with Si(100) substrates, which is the subject of present study. BFO/SRO thin films have been epitaxially grown on Si (100) substrates by introducing MgO/TiN epitaxial buffer layers using pulsed laser deposition. BFO thin films show room temperature ferroelectricity as observed from piezo force microscopy (PFM) measurements. The magnetic data collected from BFO thin films show typical antiferromagnetic features as expected. The TCof SRO in all the samples studied was found be ∼ 170K, close to the reported value of 165K. Interestingly, we have noticed that the coercive field of SRO layer increased from 4 kOe to 15 kOe (nearly fourfold) by reducing its thickness from 180 to 23nm, while keeping the thickness of BFO layer constant at 100nm. Pinning of Ru ions by ferroelectric domain walls in BFO, strong interfacial exchange coupling and SRO layer thickness could cause the observed enhancement in coercivity. Our near future work will address the precise underlying mechanisms in greater detail.

Light Scattering from Pulsed Laser Deposited BaBi4Ti4O15 Thin Films

2000 ◽  
Vol 623 ◽  
Author(s):  
R.K. Soni ◽  
Anju Dixit ◽  
R. S. Katiyar ◽  
A. Pignolet ◽  
K.M. Satyalakshmi ◽  
...  
Keyword(s):  
Thin Films ◽  
Light Scattering ◽  
Room Temperature ◽  
Layer Structure ◽  
Low Frequency ◽  
Pulsed Laser ◽  
Buffer Layers ◽  
Frequency Mode ◽  
High Frequency Vibrations ◽  
Low Frequency Mode

AbstractLight scattering investigations are carried out on BaBi4Ti4O15 (BBiT) which is a member of the Bi-layer structure ferroelectric oxide with n = 4. The BBiT thin films, thickness ∼ 300 nm, were grown on epitaxial conducting LaNiO3 electrodes on epitaxial buffer layers on (100) silicon by pulsed laser deposition. Micro-Raman measurements performed on these films reveal a sharp low-frequency mode at 51 cm−1 along with broad highfrequeficy modes corresponding to other lattice vibrations including TiO6 octahedra. No temperature dependence of the low frequency mode is seen while a weak dependence of the broad high frequency vibrations are observed in the mixed oriented regions. Raman polarization carried out at room temperature indicates that the prominent modes have Alg and Eg symmetries in the BaBi4Ti4O15 thin films.

Room-temperature preparation of biaxially textured indium tin oxide thin films with ion-beam-assisted deposition

2003 ◽  
Vol 18 (2) ◽  
pp. 442-447 ◽  
Author(s):  
Karola Thiele ◽  
Sibylle Sievers ◽  
Christian Jooss ◽  
Jörg Hoffmann ◽  
Herbert C. Freyhardt
Keyword(s):  
Thin Films ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Room Temperature ◽  
Film Growth ◽  
Texture Evolution ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Buffer Layers ◽  
Ito Thin Films

Biaxially aligned indium tin oxide (ITO) thin films were prepared by an ion-beamassisted deposition (IBAD) process at room temperature. Films with a transmittance at 550 nm of 90% and an electrical resistivity of 1.1 × 10−3 Ωcm for 300 and 250 nm thickness were obtained. Investigations of the texture evolution during IBAD film growth were carried out and compared to the well-established texture development in yttria-stabilized zirconia. An in-plane texture of 12.6° full width at half-maximum (FWHM) for a 1-μm-thick IBAD-ITO film was achieved. The quality of these films as electrically conductive buffer layers for YBa2Cu3O7-δ (YBCO) high-temperature superconductors was demonstrated by the subsequent deposition of high-currentcarrying YBCO films by thermal co-evaporation using a 3–5-nm-thick Y2O3 interlayer.A Jc of 0.76 MA/cm2 (77K, 0 T) was obtained for a 1 × 1 cm sample with ITO of 20° FWHM.

Magnetoresistance of Nanoscale Domain Walls Formed in Arrays of Parallel Nanowires

SPIN ◽  
2019 ◽  
Vol 09 (01) ◽  
pp. 1950004
Author(s):  
Jingchun Wang ◽  
Floriano Cuccureddu ◽  
Rafael Ramos ◽  
Cormac Ó. Coileáin ◽  
Igor V. Shvets ◽  
...  
Keyword(s):  
Thin Films ◽  
Domain Wall ◽  
Exchange Interaction ◽  
Exchange Bias ◽  
Room Temperature ◽  
Domain Walls ◽  
Nanowire Array ◽  
Bias Field ◽  
Nanowire Arrays ◽  
Exchange Bias Field

We present the possibility of enhancing magnetoresistance (MR) by controlling nanoscale domain wall (DW) width in a planar nanowire array. Results based on micromagnetic calculations show that DW width decreases with increasing exchange bias field and decreases with reducing exchange interaction between neighboring nanowires. Fe/Fe3O4 nanowire arrays were grown on [Formula: see text]-plane sapphire to demonstrate the feasibility of this concept, and an enhanced MR ratio of 3.7% was observed at room temperature. compared with flat and stepped Fe3O4 thin films.

scholarly journals Pulsed Laser Deposition of Nanoporous Cobalt Thin Films

2008 ◽  
Vol 8 (11) ◽  
pp. 6043-6047 ◽  
Author(s):  
Chunming Jin ◽  
Sudhakar Nori ◽  
Wei Wei ◽  
Ravi Aggarwal ◽  
Dhananjay Kumar ◽  
...  
Keyword(s):  
Thin Films ◽  
Aluminum Oxide ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Magnetic Data ◽  
Anodized Aluminum ◽  
Anodized Aluminum Oxide ◽  
Cobalt Thin Films

Nanoporous cobalt thin films were deposited on anodized aluminum oxide (AAO) membranes at room temperature using pulsed laser deposition. Scanning electron microscopy demonstrated that the nanoporous cobalt thin films retained the monodisperse pore size and high porosity of the anodized aluminum oxide substrates. Temperature- and field-dependent magnetic data obtained between 10 K and 350 K showed large hysteresis behavior in these materials. The increase of coercivity values was larger for nanoporous cobalt thin films than for multilayered cobalt/alumina thin films. The average diameter of the cobalt nanograins in the nanoporous cobalt thin films was estimated to be ∼5 nm for blocking temperatures near room temperature. These results suggest that pulsed laser deposition may be used to fabricate nanoporous magnetic materials with unusual properties for biosensing, drug delivery, data storage, and other technological applications.

ENHANCED ELECTROCALORIC PROPERTIES OF PMN-PT THIN FILMS WITH LSCO BUFFER LAYERS

2011 ◽  
Vol 04 (01) ◽  
pp. 45-48 ◽  
Author(s):  
Y. HE ◽  
X. M. LI ◽  
X. D. GAO ◽  
X. LENG ◽  
W. WANG
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Lead Titanate ◽  
Room Temperature ◽  
Ferroelectric Properties ◽  
Lead Magnesium Niobate ◽  
Buffer Layers ◽  
Lanthanum Strontium ◽  
Method Effects ◽  
Lead Magnesium

Lead magnesium niobate-lead titanate (PMN-PT) ferroelectric thin films were deposited on Ir/SrTiO3/TiN/Si (001) substrates by oxygen plasma assisted pulsed laser deposition (PLD) method. Effects of the lanthanum strontium cobaltite (LSCO) buffer layer between the PMN-PT film and the Ir layer on the crystallinity, microstructure, ferroelectric properties and electrocaloric effect of the film were investigated. Results show that the LSCO buffer layer can improve the crystallinity and electrocaloric properties effectively. By applying a voltage of 5V to the PMN-PT thin film without the LSCO buffer layer, the changes in the reversible adiabatic temperature measured at room temperature and at 508 K are respectively 0.73 K and 2.13 K, while by introducing a LSCO buffer layer, the corresponding values are increased to 1.41 K and 4.25 K.

Study of the growth mechanism and properties of InN films grown by MOCVD

2003 ◽  
Vol 798 ◽  
Author(s):  
Abhishek Jain ◽  
Joan M. Redwing
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Growth Temperature ◽  
Room Temperature ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Film Morphology ◽  
Buffer Layer Thickness ◽  
Aln Buffer

ABSTRACTThin films of InN were grown on (0001) Sapphire by MOCVD. The effect of growth conditions and buffer layer on the film morphology was studied. Growth temperature and TMI flow rate were important factors in the growth of InN. The use of a low temperature AlN buffer layer was also found to improve the morphology and crystal quality of the films. Thin (<40Å) AlN buffer layers produced the best results while polycrystalline InN was obtained when the buffer layer thickness exceeded 60Å. Delamination of the InN films was observed to occur at growth temperature, which limited the thickness of the films to less than 300 nm. A room temperature mobility of 792 cm2/Vs and an electron concentration of 2.1×1019 cm-3 were measured in an approximately 200 nm thick InN layer grown on sapphire.

scholarly journals Optical Properties of Highly Conductive SrMoO3 Oxide Thin Films in the THz Band and Beyond

2020 ◽  
Vol 41 (10) ◽  
pp. 1170-1180
Author(s):  
Stefan Regensburger ◽  
Mahdad Mohammadi ◽  
Arslan A. Khawaja ◽  
Aldin Radetinac ◽  
Philipp Komissinskiy ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Gold Film ◽  
Laser Deposition ◽  
Oxide Thin Film ◽  
Electromagnetic Spectrum ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Visible Part

Abstract Strontium molybdate (SrMoO3) thin films are grown epitaxially by pulsed laser deposition onto gadolinium scandate (GdScO3) substrates and characterized in the terahertz (THz) and visible part of the electromagnetic spectrum. X-ray diffraction measurements prove a high crystallinity and phase-pure growth of the thin films. The high-quality SrMoO3 thin films feature a room temperature DC conductivity of around $3{\frac {1}{\mu {\Omega } m}}$ 3 1 μ Ω m . SrMoO3 is characterized in the THz frequency range by time domain spectroscopy. The resulting AC conductivity is in excellent agreement with the DC value. A Lorentz-Drude oscillator approach models the THz and visible conductivity of SrMoO3 very well. We compare the results of the SrMoO3 thin films to a standard, sputtered gold film, with a resulting THz conductivity of $8{\frac {1}{\mu {\Omega } m}}$ 8 1 μ Ω m . The comparison demonstrates that oxide thin film–based devices can play an important role in future THz technology.

scholarly journals H2O2Treatment of Electrochemically Deposited Cu2O Thin Films for Enhancing Optical Absorption

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ying Song ◽  
Masaya Ichimura
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Room Temperature ◽  
Oxide Thin Film ◽  
Fixed Temperature ◽  
Electrochemically Deposited ◽  
Oxygen Ratio ◽  
Copper Oxide Thin Film

Cu2O is considered to be promising as an absorber layer material of solar cells, but its band gap (about 2.1 eV) is larger than the optimum one (about 1.5 eV). CuO has a smaller band gap of about 1.35 eV. Therefore, we attempted to oxidize Cu2O using H2O2to increase oxygen ratio and decrease band gap. Cu2O thin films were deposited on indium-tin-oxide-coated glass from an aqueous solution containing CuSO4, lactic acid, and KOH by the galvanostatic electrochemical deposition at 40°C with current density of −1 mA/cm2. Then, the as-prepared copper oxide thin film was dipped in H2O2(30%) at fixed temperature to oxidize for some time. By the H2O2treatment at room temperature, the oxygen content was increased, and the band gap was decreased.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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