Theoretical study on local domain pinning effect due to defect dipole alignment

Acoustic Emission (AE) and hysteresis parameters were studied from PZT-5A (soft) and PZT-8 (hard) ceramics during the application of ac fields in the frequency range of 0.2 Hz to 5 Hz. AE was found to occur mainly due to domain switching in these ceramics during the application of ac fields. In PZT-5A, a threshold field was observed for the AE activity to begin in both the direction of the applied field and in general, it was found to decrease with increasing frequency. Apart from this, AE activity was found to decrease with increasing number of applied ac cycles, and is attributed to domain pinning. In the case of PZT-8, AE was found to occur even at zero field at higher frequencies and AE activity was found to increase with increasing number of field cycles. These are explained on the basis of the defect dipole — domain interaction in these ceramics.

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Influence of short-range artificial defects in a macroscopic flat disk on the Abrikosov state

International Journal of Modern Physics B ◽

10.1142/s0217979214502270 ◽

2014 ◽

Vol 28 (32) ◽

pp. 1450227 ◽

Cited By ~ 4

Author(s):

Jesús González Acosta ◽

Miryam R. Joya ◽

J. Barba-Ortega

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Short Range ◽

Theoretical Study ◽

Thin Disk ◽

Cooper Pairs ◽

Vortex Pattern ◽

Pinning Effect ◽

Flat Disk ◽

Barrier Defect

We study the vortex configuration in a superconducting macroscopic flat disk with central defects in the presence of a uniform applied magnetic field. Owing to the defects nature on the thin disk, vortices are able to form geometry induced, quasi-symmetric configurations of disk, triangle and concentric shells in the rest of the disk. The theoretical study made on this mesoscopic systems allows us to trace not only how the vortex pattern evolves with magnetic field, but also how the defect can be used to show the pinning and anti-pinning effect. The magnetic induction, vortex number, magnetization and Cooper pairs density as a function of the external magnetic field are calculated, we show that in our sample novels vortex configurations are possible due to the size of the disk and if the hole or barrier defect is considered.

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Enhancement of Ferroelectric Curie Temperature in BaTiO3Films via Strain-Induced Defect Dipole Alignment

Advanced Materials ◽

10.1002/adma.201400254 ◽

2014 ◽

Vol 26 (36) ◽

pp. 6341-6347 ◽

Cited By ~ 76

Author(s):

Anoop R. Damodaran ◽

Eric Breckenfeld ◽

Zuhuang Chen ◽

Sungki Lee ◽

Lane W. Martin

Keyword(s):

Curie Temperature ◽

Defect Dipole ◽

Dipole Alignment

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Xenon ion irradiation of superconducting YBa2Cu3O7 thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173595 ◽

1990 ◽

Vol 48 (4) ◽

pp. 92-93

Author(s):

H. Watanabe ◽

B. Kabius ◽

B. Roas ◽

K. Urban

Keyword(s):

Defect Formation ◽

Ion Irradiation ◽

High Resolution Electron Microscopy ◽

Structural Disorder ◽

Flux Lines ◽

Pinning Effect ◽

Magnetic Flux Lines ◽

Resolution Electron ◽

Radiation Induced ◽

Induced Defects

Recently it was reported that the critical current density(Jc) of YBa2Cu2O7, in the presence of magnetic field, is enhanced by ion irradiation. The enhancement is thought to be due to the pinning of the magnetic flux lines by radiation-induced defects or by structural disorder. The aim of the present study was to understand the fundamental mechanisms of the defect formation in association with the pinning effect in YBa2Cu3O7 by means of high-resolution electron microscopy(HRTEM).The YBa2Cu3O7 specimens were prepared by laser ablation in an insitu process. During deposition, a substrate temperature and oxygen atmosphere were kept at about 1073 K and 0.4 mbar, respectively. In this way high quality epitaxially films can be obtained with the caxis parallel to the <100 > SrTiO3 substrate normal. The specimens were irradiated at a temperature of 77 K with 173 MeV Xe ions up to a dose of 3.0 × 1016 m−2.

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