Thin Ferroelectric Film between Double Schottky Barriers

2004 ◽  
Vol 830 ◽  
Author(s):  
Lyuba A. Delimova ◽  
Igor V. Grekhov ◽  
Dmitri V. Mashovets ◽  
Sangmin Shin ◽  
June-Mo Koo ◽  
...  
Keyword(s):  
Film Thickness ◽  
Poisson Equation ◽  
Electric Fields ◽  
Field Potential ◽  
Ferroelectric Film ◽  
Schottky Barriers ◽  
Flat Band ◽  
External Bias ◽  
The Poisson Equation ◽  
Type Semiconductor

ABSTRACTThin-film uniform metal-ferroelectric-metal (M/F/M) structure between back-to-back Schottky barriers (SBs) is considered. The ferroelectric is assumed to be a p-type semiconductor, and the film thickness is far less than the depletion layer induced by the S.B. Numerical integration of the Poisson equation is used to analyze the influence of double Shottky barriers on the distributions of the electric field, potential, and polarization across the film thickness as functions of external bias and the film electrical history. The range of structure parameters is determined, where the Poisson equation for M/F/M structure can be solved analytically providing an obvious and easy-to-interpret representation of the M/F/M behavior. Electric fields induced by back-to-back SBs under zero external bias compensate each other to a great extent. As a result, the potential across the ferroelectric film remains virtually unchanged providing the flat-band condition in the energy diagram of zero-biased M/F/M structure; in fact, the external bias applied to M/F/M structure exerts influence only on the reverse-biased barrier.

Trap Charge Density at Interfaces of MOCVD Pt(Ir)/PZT/Ir(Ti/SiO2/Si) Structures

2005 ◽  
Vol 902 ◽  
Author(s):  
Lyuba A. Delimova ◽  
I. V. Grekhov ◽  
D. V. Mashovets ◽  
Sangmin Shin ◽  
June-Mo Koo ◽  
...  
Keyword(s):  
Charge Density ◽  
Metal Structure ◽  
Ferroelectric Film ◽  
Schottky Barriers ◽  
Trap Density ◽  
Transient Current ◽  
Interface Traps ◽  
Trap Charge ◽  
External Bias ◽  
Bias Pulse

AbstractA method providing estimation of the trap density at metal/ferroelectric interfaces of a depleted ferroelectric film located between back-to-back Schottky barriers has been developed. The method is based on the recharge of interface traps induced by external bias pulse applied to the metal/ferroelectric/metal structure. It is shown that the transient current under bias pulse can be controlled by the traps recharge on the reverse-biased interface. Using the method, the trap charge density on interfaces of MOCVD Pt/PZT/Ir(Ti/SiO2/Si) and Ir/PZT/Ir(Ti/SiO2/Si) capacitors were found from transient current measurements.

Grad-Shafranov reconstruction of the in-plane magnetic field potential in the X-point vicinity: boundary-layer approximation

2020 ◽  
Author(s):  
Daniil Korovinskiy ◽  
Andrey Divin ◽  
Vladimir Semenov ◽  
Nikolai Erkaev ◽  
Stefan Kiehas
Keyword(s):  
Boundary Layer ◽  
Poisson Equation ◽  
Field Potential ◽  
Boundary Layer Approximation ◽  
The Poisson Equation ◽  
Right Hand ◽  
Reconnection Region ◽  
Out Of Plane ◽  
Shafranov Equation ◽  
The Right

<p>The problem of steady symmetrical two-dimensional magnetic reconnection is addressed in terms of the EMHD approximation. In the immediate vicinity of the X-point, this approach has been proven to be an appropriate frame for the reconstruction problem, expressed, particularly, by the Poisson equation for the magnetic potential <em>A</em>, where the right-hand side contains the out-of-plane electron current density with reversed sign. With boundary conditions fixed at some curve (the satellite trajectory), and assuming the right-hand side to be a function of <em>A</em>, one arrives at an ill-posed problem for the Grad-Shafranov equation. The further simplification of the problem may be achieved by using the boundary layer approximation, since magnetic configuration in reconnection region is highly stretched. The benchmark reconstruction of PIC-simulation data, using four numerical techniques, has shown that the main contribution for inaccuracy arises from replacing the Poisson equation by the Grad-Shafranov one. A boundary layer approximation, in turn, does not affect the accuracy significantly; in some cases this approach can appear even the most appropriate. </p>

Comparison of random field strengths in (1-x)SrTiO3-xBiFeO3 and (1-x)SrTiO3-xBaTiO3 relaxor ferroelectrics by means of acoustic emission

2020 ◽  
Vol 92 (2) ◽  
pp. 20401
Author(s):  
Evgeniy Dul'kin ◽  
Michael Roth
Keyword(s):  
Acoustic Emission ◽  
Random Field ◽  
Electric Fields ◽  
Bias Field ◽  
Relaxor Ferroelectrics ◽  
External Bias ◽  
Field Strengths

In relaxor (1-x)SrTiO3-xBiFeO3 ferroelectrics ceramics (x = 0.2, 0.3 and 0.4) both intermediate temperatures and Burns temperatures were successfully detected and their behavior were investigated in dependence on an external bias field using an acoustic emission. All these temperatures exhibit a non-trivial behavior, i.e. attain the minima at some threshold fields as a bias field enhances. It is established that the threshold fields decrease as x increases in (1-x)SrTiO3-xBiFeO3, as it previously observed in (1-x)SrTiO3-xBaTiO3 (E. Dul'kin, J. Zhai, M. Roth, Phys. Status Solidi B 252, 2079 (2015)). Based on the data of the threshold fields the mechanisms of arising of random electric fields are discussed and their strengths are compared in both these relaxor ferroelectrics.

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