Thermally Stimulated Current (TSC) Studies on Resistance Degradation of Ni-MLCC

Abstract

To avoid the influence of spontaneous polarization, thermally stimulated current (TSC) measurements of BaTiO 3 -based multilayer ceramic capacitors with Ni internal electrodes were performed within the paraelectric phase. We observed two TSC peaks and inferred that one of them was related to the resistance degradation according to the electromigration of oxygen vacancies. Further, we proposed that the two peaks resulted from the relaxation phenomenon of the oxygen vacancies, which migrated under dc electrical field stresses, in the grains and over the grain boundaries.

Dielectric response and thermally stimulated depolarization current analysis of BaNd1.76Bi0.24Ti5O14 high-temperature microwave capacitors

“…Meanwhile, the activation energy values of peak B are in the range of 0.64-0.76 eV and the average value is 0.71 eV. According to the movement of relaxation peaks and the activation energy value, it can be concluded that the relaxation peak B should be generated by oxygen vacancies (V O ) [16][17][18][19][20][21][22]. By comparing the activation energies of peak A and peak B, it can be concluded that peak A shows the higher value than peak B.…”

“…10b that the V O relaxation shows a long relaxation time in the range of 160-930 ls and an increase tendency with TSDC peak density, which is correlated with the migration of the polarized oxygen vacancies in dielectrics. The oxygen vacancies are depleted in the anodic region and piled-up in the cathodic region after polarization [16][17][18][19][20][21][22]. Under the suitable polarization conditions, some oxygen vacancies can migrate across the grain boundaries into adjacent grains.…”

“…The polarization time is 10 min and the heating rate is 6°C/min typical characteristic of space-charge polarization. Therefore, peak B is considered to be mainly from the relaxation of the mobile oxygen vacancies [16][17][18][19]21].…”

“…TSDC may also be used to evaluate the activation energy of relaxation, relaxation time and the defect concentration, which enables a better understanding of the physical phenomena related to such defects [10,11,[15][16][17][18]. TSDC is frequently used to analyze polymer materials; however, TSDC is yet to be extensively employed on microwave dielectrics [16][17][18][19][20][21][22][23][24]. The measurement of TSDC spectra is briefly described as follows [17][18][19][20].…”

“…[16][17][18][19][20][21][22][23][24]. TSDC may also be used to evaluate the activation energy of relaxation, relaxation time and the defect concentration, which enables a better understanding of the physical phenomena related to such defects [10,11,[15][16][17][18].…”