Microwave characteristics of BaPr2Ti4O12 and BaPr2Ti5O14 ceramics

Fukuda, Koichi; Kitoh, Ryozo; Awai, Ikuo

doi:10.1557/jmr.1995.0312

Cited by 23 publications

(4 citation statements)

References 13 publications

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“…Negas et al [28] observed similar variations for Smand Nd-based ceramics. Fukuda et al [76] found a similar enhancement of Qf at x = 2/3 in Ba 6-3x Pr 8 þ 2x Ti 18 O 54 . At x = 2/3, Ln and Ba ions occupy separately the rhombic sites (A1) and the pentagonal sites (A2) respectively and at this composition the ceramics showed a maxima in Qf.…”

Section: Dielectric Propertiesmentioning

confidence: 72%

“…Several authors studied [3,5,10,11,13,16,19,21,29,41,57,56,[66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84] the dielectric properties of Ba 6-3x Ln 8 þ 2x Ti 18 O 54 ceramics for different values of x and Ln = La, Pr, Sm, Nd, Eu, Gd and are given in Table 5.3. A study of Table 5.3 shows that the ceramics based on Eu, Sm and Nd have high quality factors (Qf) up to 14 000 GHz.…”

Section: Dielectric Propertiesmentioning

confidence: 99%

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Pseudo-Tungsten Bronze-Type Dielectric Materials

Sebastian

2008

Dielectric Materials for Wireless Communication

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Section: Dielectric Propertiesmentioning

confidence: 72%

Section: Dielectric Propertiesmentioning

confidence: 99%

Pseudo-Tungsten Bronze-Type Dielectric Materials

Sebastian

2008

Dielectric Materials for Wireless Communication

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“…TTB thin film exhibits a permittivity ε r = 135 at 10 GHz, 130 at 20 GHz, and 125 at 30 GHz showing a good stability versus frequency (Figure 11a). Even though the literature does not present many microwave dielectric characterizations of the TTB phases, permittivity values close to 130 have also been reported for other materials [45,46]. Nevertheless, these values remain lower than those retrieved from the K x Na 1-x NbO 3 perovskite phase in the same settings [47].…”

Section: High Frequency Measurementsmentioning

confidence: 76%

Tetragonal tungsten bronze phase thin films in the K–Na–Nb–O system: Pulsed laser deposition, structural and dielectric characterizations

Aspe

Demange

Waroquet

et al. 2020

Journal of Alloys and Compounds

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Pulsed laser deposition parameters have been determined to synthesize pure Tetragonal Tungsten Bronze (TTB) phase thin films in the (K , Na)-Nb-O system (KNN). In relation to the high volatility of alkaline elements, it was found that the target composition and the targetsubstrate distance are of first importance. The TTB phase was identified by X-ray and electron diffraction and the surface microstructure consisting mainly of nanorods supports the formation of hallmark of the TTB phase. Poly-oriented nanorods have been obtained on both C-plane sapphire and (111)Pt/TiO 2 /SiO 2 /(001)Si substrates whereas horizontal nanorods oriented along the (hk0) planes have been grown on (100) and (110) SrTiO 3. All the nanorods are parallel together when grown on (110) SrTiO 3 and they present two in-plane orientations rotated of 90° from each other on (100) SrTiO 3. Dielectric characteristics (dielectric permittivity ε r , and loss tangent tanδ) have been measured at low (1 kHz-1 MHz) and high (1 GHz-40 GHz) frequencies, on films deposited on Pt coated silicon and sapphire, respectively. A value of ε r = 200 at 1 kHz with tanδ = 0.015 were measured in a parallel plate capacitor configuration, whereas ε r = 130 and tanδ = 0.20 at 10 GHz were retrieved from transmission lines printed on the KNN TTB thin film grown on C-plane sapphire. Raman investigations of the TTB films were performed in the temperature range 77-873 K, confirming the TTB phase formation and the absence of structural transition. Piezoelectric Force Microscopy measurements evidenced a piezoelectric signal although no switching could be performed. However the dielectric measurements, complicated by high leakage currents when a DC voltage was applied, did not evidence any proof of ferroelectricity for the undoped KNN TTB films whereas results reported on other niobates (A,A') 0.6 Nb 10 O 30 (with A: K, Na and A': Sr, Ba, Ca) have shown Curie temperatures, lying between 156°C and 560°C, separating the paraelectric phase (space group: P4/mbm N°127) and the ferroelectric one (space group: P4bm N°100).

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“…Clearly, the trend is violated by Gd which, although smaller than Eu, exhibits a very low Q• f value of 2050 GHz. [3][4][5][6][7] The samples for the dielectric property measurements were prepared from reagent-grade BaCO 3 , Sm 2 O 3 , and TiO 2 . The starting reagents were mixed in the appropriate ratios and homogenized by ball milling.…”

mentioning

confidence: 99%