PENGUKURAN NILAI DIELEKTRIK MATERIAL CALCIUM COPPER TITANAT ( CaCu3Ti4O12) MENGGUNAKAN SPEKTROSKOPI IMPEDANSI TERKOMPUTERISASI

Telah dilakukan pengukuran tetapan dielektrik kompleks dan besarnya impedansi kapasitor pada material keramik Calcium Copper Titanate dengan struktur material CaCu3Ti4O12 (CCTO) dengan kemurnian 99 % menggunakan metode spektroskopi impedansi terkomputerisasi dalam rentang frekuensi 5 kHz – 120 kHz. Tetapan dielektrik maksimum terukur pada sampel yang disintering dengan suhu 7000C yaitu 745 pada frekuensi 5 kHz dan besarnya impedansi kapasitor maksimum terjadi pada sampel CCTO non sintering yaitu 150434 Ω. Hasil penelitian menunjukkan adanya pengaruh frekuensi terhadap tetapan dielektrik kompleks dan impedansi kapasitor dari material yang diteliti. Kata kunci : spektroskopi impedansi, CaCu3Ti4O12, tetapan dielektrik kompleks dan impedansi kapasitor. MEASUREMENT OF THE DIELECTRIC CONSTANT CALCIUM COPPER TITANATE (CaCu3Ti4O12) MATERIALS USING COMPUTERIZED IMPEDANCE SPECTROSCOPY ABSTRACT The measurement of the complex dielectric constant and the magnitude of the capacitor impedances of the ceramic materials Calcium Copper Titanate CaCu3Ti4O12 (CCTO) with purity of 99% has been done by using the method of computerized impedance spectroscopy in the frequency range 5 kHz - 120 kHz. The highest dielectric constant of the material was found to be 745 at 5 kHz in the sample sintered 7000C and the highest impedance of capacitor occured in CCTO sample non sintered that is 150434Ω. The results showed that complex dielectric constant and impedance of the capacitor of the material under study was frequency dependent. Keywords : impedance spectroscopy, CaCu3Ti4O12,complex dielectric constant and impedance of capacitor

Effect of Glass Addition on the Properties of CaCu3Ti4O12 Ceramics

The effect of glass addition on the properties of CaCu3Ti4O12 (CCTO) ceramics was studied. CCTO ceramics with BaO-SrO-Nb2O5-B2O3-SiO2 (BSNBS) glass additive were prepared using solid state reaction method. The raw materials of CCTO and BSNBS were wet mixed separately for 24 hours, dried overnight and subsequently the BSNBS powders was melted at 1450°C for 2 hours while CCTO powders was calcined at 900°C for 12 hours. BSNBS glass then was grinded to form a fine powders. Different weight percentages of BSNBS powder were added into CCTO and the powders were wet mixed at 24 hours. The mixtures were dried, compacted at 250 MPa and then sintered at 1050°C for 10 hours. X-Ray Diffractometer (XRD) analysis showed the formation of CCTO phase for all sintered samples while secondary phase of CuO phase was identified for sintered BSNBS 1.0 sample. Observation on Scanning Electron Microscopy (SEM) micrographs showed abnormal grain growth was seen in CCTO sample and grain size of the samples become finer with increasing the concentration glass addition. CCTO sample obtained the highest dielectric constant (8670) while the lowest dielectric loss (0.38) was recorded by BSNBS 0.10 sample, measured at 1 MHz.

Improved Electrical Properties of BaTiO3 – coated CaCu3Ti4O12 Dielectrics

ABSTRACTWe report a significant improvement in the electrical properties of CaCu3Ti4O12 (CCTO) dielectrics by the BaTiO3 (BTO) additive. The addition of BTO to CCTO was performed using two different methods of a solid-state mixing and a sol-gel coating. Compared with pure CCTO ceramics (εr ∼ 52,000 and tanδ ∼ 0.38 at 100 kHz), BTO-added CCTO samples commonly showed a large improvement in the dielectric loss property although their dielectric constants were depressed around one order of magnitude; εr ∼ 5900 and tanδ ∼0.05 for 5 mol% BTO-coated CCTO sample and εr ∼ 4,075 and tanδ ∼ 0.02 for 5 mol% BTO-mixed CCTO sample. In addition, BTO-coated CCTO samples showed relatively lower leakage current than those of BTO-mixed CCTO samples, implying that the sol-gel coating is more effective for improving the electrical properties of CCTO.

Microstructures and Dielectric Properties of CaCu3Ti4O12 Polycrystalline Ceramics

We report important factors affecting the dielectric properties of CaCu3Ti4O12 (CCTO) polycrystalline ceramics prepared by the conventional solid-state ceramic process. The relative dielectric constants (εr) up to several thousands (~ 3,000 at 1 kHz) were gradually increased with increasing the sintered density of samples in the case that no exaggerated grain growth occurred. An abrupt increase in εr values were, however, accompanied by the formation of abnormally grown large grains, and thus with increasing the population of abnormally grown grains, which could be achieved by a prolonged sintering at 1060°C, the εr values were remarkably increased from several thousands to ~105. Optimally processed CCTO sample exhibited a very high εr of ~ 90,000 at 1 kHz.