Engineered Biferroic 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3/La0.6Sr0.4MnO3 Epitaxial Superlattices

2007 ◽  
Vol 1034 ◽  
Author(s):  
Ayan Roy Chaudhuri ◽  
S.B. Krupanidhi

AbstractSymmetric and asymmetric superlattices (SLs) composed of ferromagnetic La0.6Sr0.4MnO3 (LSMO) and ferroelectric 0.7Pb(Mg1/3Nb2/3)O3 – 0.3PbTiO3 (PMN-PT) with different periodicities have been fabricated on LaNiO3 (LNO) coated LaAlO3 (100) (LAO) substrates by pulsed laser ablation deposition. Structural, ferromagnetic and ferroelectric properties have been studied for all the SLs. All the heterostructures exhibited good ferromagnetic response over a wide range of temperatures (10K – 300K), whereas only the asymmetric SLs exhibited reasonably good ferroelectric behaviour. Ferromagnetic and ferroelectric hysteresis loops observed in the asymmetric SLs confirmed their biferroic nature. Studies were conducted towards understanding the influence of LSMO layers on the electrical responses of the heterostructures. Absence of ferroelectricity in the symmetric SL structures has been attributed to their high leakage characteristics. Strong influence of an applied magnetic field of 1.2T was observed on the ferroelectric properties of the asymmetric SLs. The effect of magnetic field on the ferroelectric properties of the SLs indicated possibility of strong interfacial effect.

2009 ◽  
Vol 1199 ◽  
Author(s):  
Ricardo Martinez ◽  
Ashok Kumar ◽  
Ratnakar Palai ◽  
Ram S. Katiyar

AbstractAsymmetric superlattices (SLs) with ferromagnetic La0.7Sr0.3MnO3 (LSMO) and ferroelectric Ba0.7Sr0.3TiO3 (BST) as constitutive layers were fabricated on conducting LaNiO3 (LNO) coated (001) oriented MgO substrates using pulsed laser deposition (PLD). The crystallinity, ferroelectric and magnetic properties of the SLs were studied over a wide range of temperatures and frequencies. The structure exhibited ferromagnetic behavior at 300K, and ferroelectric behavior over a range of temperatures between 100K and 300K. The dielectric response as a function of frequency obeys normal behavior below 300 K, whereas it follows Maxwell–Wagner model at elevated temperatures. The effect of ferromagnetic LSMO layers on ferroelectric properties of the SL indicated strong influence of the interfaces. The asymmetric behavior of ferroelectric loop and the capacitance-voltage relationship suggest development of a built field in the SLs due to high strain across the interfaces.


2001 ◽  
Vol 688 ◽  
Author(s):  
J. Rodríguez Contreras ◽  
J. Schubert ◽  
U. Poppe ◽  
O. Trithaveesak ◽  
K. Szot ◽  
...  

AbstractWe have prepared single crystalline epitaxial PbZr0.52Ti0.48O3 (PZT) and BaTiO3 (BTO) thin films on single crystalline epitaxial SrRuO3 (SRO) thin films grown on SrTiO3 (100) (STO) substrates. PZT and SRO thin films were grown using high-pressure on-axis sputtering and BTO using pulsed laser deposition (PLD). The film thickness ranged between 12 to 165 nm. Their excellent structural properties, surface smoothness and interface sharpness were demonstrated by X-Ray Diffraction measurements (XRD), High Resolution Transmission Electron Microscopy (HRTEM) and Atomic Force Microscopy (AFM). Rutherford Backscattering Spectrometry and Channeling measurements (RBS/C) were used to analyze stoichiometry and crystalline quality. Ferroelectric hysteresis loops were obtained for all films of a thickness down to 12 nm showing a decrease in the remanent polarization Pr and an increase in the coercive field Ec towards thinner film thicknesses. Furthermore we have prepared tunneling junctions with a PZT or BTO barrier thickness of 3-6 nm. Reproducible bi-stable I-V-curves and bias dependence of the conductance were obtained suggesting an influence of the ferroelectric properties of the barrier material on the tunnel current.


2007 ◽  
Vol 14 (02) ◽  
pp. 229-234
Author(s):  
SARAWUT THOUNTOM ◽  
MANOCH NAKSATA ◽  
KENNETH MACKENZIE ◽  
TAWEE TUNKASIRI

Lead zirconate titanate (PZT) films with compositions near the morphotropic phase boundary were fabricated on Pt (111)/ Ti / SiO 2/ Si (100) using the triol sol–gel method. The effect of the pre-heating temperature on the phase transformations, microstructures, electrical properties, and ferroelectric properties of the PZT thin films was investigated. Randomly oriented PZT thin films pre-heated at 400°C for 10 min and annealed at 600°C for 30 min showed well-defined ferroelectric hysteresis loops with a remnant polarization of 26.57 μC/cm2 and a coercive field of 115.42 kV/cm. The dielectric constant and dielectric loss of the PZT films were 621 and 0.0395, respectively. The microstructures of the thin films are dense, crack-free, and homogeneous with fine grains about 15–20 nm in size.


1998 ◽  
Vol 20 (1-4) ◽  
pp. 79-86 ◽  
Author(s):  
Pingxiong Yang ◽  
Lirong Zheng ◽  
Chenglu Lin ◽  
Wenbiao Wu ◽  
Masanori Okuyama

2010 ◽  
Vol 177 ◽  
pp. 197-200
Author(s):  
X.A. Mei ◽  
Min Chen ◽  
K.L. Su ◽  
A.H. Cai ◽  
J. Liu ◽  
...  

Eu2O3-doped bismuth titanate (Bi1-xEuxTi3O12: BET) thin films with random oriention were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique, and the structures and ferroelectric properties of the films were investigated. XRD studies indicated that all of BET films consisted of single phase of a bismuth-layered structure with well-developed rod-like grains. For samples with x=0.0 , 0.25, 1.0 and 1.25, I-E characteristics exhibited negative differential resistance behaviors and their ferroelectric hysteresis loops were characterized by large leakage current, whereas for samples with x=0.5 and 0.75, I-E characteristics were simple ohmic behaviors and their ferroelectric hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization (Pr) and coercive field (Ec) of the BET Film with x=0.75 were above 30μC/cm2 and 85KV/cm , respectively.


Author(s):  
Vincensius Gunawan ◽  
Ngurah Ayu Ketut Umiati

<p>We present a theoretical discussion of the hysteresis in magnetoelectric multiferroics with bi-quadratic magnetoelectric coupling. The calculations were performed by employing Landau-Khalatnikov equation of motion for both the ferroelectric and ferromagnetic phase, then solve it simultaneously. In magnetoelectric, we obtain four types of hysteresis: ferroelectric hysteresis, ferromagnetic hysteresis and two types of cross hysteresis (electric field versus magnetization and magnetic field versus electric polarization). The cross hysteresis has butterfly shape which agree with the result from the previous research. It can also be seen from that hysteresis, that magnetization / electric polarization can not be flipped into the opposite direction using external electric / magnetic field when the magnetoelectric coupling is bi-quadratic type. Overall, the result shows that Landau-Khalatnikov equation is able to approximate hysteresis loops in multiferroics system.</p>


2010 ◽  
Vol 434-435 ◽  
pp. 281-284
Author(s):  
Min Chen ◽  
A.H. Cai ◽  
X.A. Mei ◽  
K.L. Su ◽  
Chong Qing Huang ◽  
...  

Pr6O11-doped bismuth titanate (BixPryTi3O12: BPT) thin films with random oriention were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique, and the structures and ferroelectric properties of the films were investigated. XRD studies indicated that all of BPT films consisted of single phase of a bismuth-layered structure with well-developed rod-like grains. For samples with y=0.06, 0.3, 1.2 and 1.5, ferroelectric hysteresis loops were characterized by large leakage current, whereas for samples with y=0.6 and 0.9, ferroelectric hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BPT Film with y=0.9 were above 35μC/cm2 and 80KV/cm , respectively. After 3×1010 switching cycles, 20% degradation of 2Pr is observed in the film with y=0.9.


1999 ◽  
Vol 14 (3) ◽  
pp. 940-947 ◽  
Author(s):  
Sucharita Madhukar ◽  
S. Aggarwal ◽  
A. M. Dhote ◽  
R. Ramesh ◽  
S. B. Samavedam ◽  
...  

We report on the feasibility of using molybdenum silicide as a conducting barrier for integration of ferroelectric lead zirconate titanate capacitors on Si. Thin films of MoSi2 were deposited by pulsed laser-ablation deposition (PLD). The silicide films showed a structural transition from amorphous to orthorhombic to tetragonal phase as the temperature of deposition was changed from room temperature to 900 °C. The four-probe resistivity and surface roughness of the films decreased with an increase in the deposition temperature and crystallinity of the phase. Ferroelectric (La, Sr)CoO3/Pb(Nb, Zr, Ti)O3/(La, Sr)CoO3 capacitors were grown on Si/poly Si/MoSi2, and Si/poly Si/MoSi2/Pt structures. Transmission electron microscopy (TEM) studies of the MoSi2/LSCO and MoSi2/Pt/LSCO heterostructures indicated the formation of a thin layer of SiO2. In the case of Pt/MoSi2, Pt reacts with the silicide and forms PtSi, consuming the entire platinum layer and, thus, makes it unsuitable as a composite barrier. Electrical testing of the LSCO/PNZT/LSCO capacitors through capacitive coupling showed desirable ferroelectric properties on these substrates.


2006 ◽  
Vol 89 (3) ◽  
pp. 032901 ◽  
Author(s):  
Zhenxiang Cheng ◽  
Chinna Venkatasamy Kannan ◽  
Kiyoshi Ozawa ◽  
Hideo Kimura ◽  
Xiaolin Wang

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