Temperature and frequency dependence of dielectric loss of Ba(Mg1/3Ta2/3)O3 microwave ceramics

Shimada, Takeshi; Ichikawa, K.; Minemura, Tetsuroh; Kolodiazhnyi, Taras; Breeze, Jonathan; Alford, Neil McN.; Annino, G.

doi:10.1016/j.jeurceramsoc.2009.04.027

Cited by 17 publications

(7 citation statements)

References 9 publications

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“…On the other hand, the loss tangent of the MTO with x = 0 5 and 1.0 wt% is higher in the temperature range of 6.5-90 K and gradually decreases with an increase in measurement temperature. Similar type of result was reported by Shimada et al 29 in the Ba(Mg 1/3 Ta 2/3 )O 3 ceramics systems measured in the temperature range of 20-300 K with an loss peak at 40 K. They suggested that the loss peak was caused by the local orientation polarization having dispersion at the microwave frequency. This peculiar frequency dependence of the dielectric loss is well described by dividing into two contributions as reported by Zuccaro et al 30 One contribution is a microwave absorption by two phonon difference process and another is an orientation polarization resonance occurring at the microwave frequency.…”

Section: Low-temperature Dielectric Measurementsupporting

confidence: 87%

Low temperature and broadband dielectric properties of V₂O₅ doped Mg₂TiO₄ ceramics

Bhuyan¹,

Kumar²,

Pamu³

et al. 2014

mat express

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The liquid phase effect of V 2 O 5 on the densification, microstructure and microwave dielectric properties of Mg 2 TiO 4 (MTO) ceramics has been investigated. The addition of V 2 O 5 significantly lowered the sintering temperature compared to pure MTO ceramics with improved microstructure, relative density and microwave dielectric properties. The increase in relative density and average grain size via growth of large grains and dissolution of small grains is explained by Ostwald ripening phenomena. Further, the microwave dielectric properties of the pure and MTO with V 2 O 5 samples were measured at cryogenic temperatures. It was observed that the loss tangent (tan ) and Q × f o of pure MTO increased with temperature, whereas the loss tangent and Q × f o of the samples with V 2 O 5 decreased with a rise in temperature. However, the MTO ceramics added with 0.5 and 1.0 wt% of V 2 O 5 manifested slightly higher loss tangents as compared to the pure MTO ceramics. The mechanism of the microwave loss is in agreement with the theory of intrinsic dielectric loss derived from the two phonon difference process. Further, the distinctive loss peak at 40 K is attributed to the orientation polarization having dispersion at the microwave frequency. The addition of V 2 O 5 did not cause any changes on the temperature stability of the MTO ceramics, whereas the temperature coefficient of the permittivity increases with an increase in temperature. The broadband dielectric measurement reveals that the V 2 O 5 doping increases the dielectric constant and enhances the stability over a wide frequency range, and shows a peak around 1.8 GHz. The tan of pure MTO still shows the peak whereas the samples doped with V 2 O 5 suppresses this peak significantly.

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Section: Low-temperature Dielectric Measurementsupporting

confidence: 87%

Low temperature and broadband dielectric properties of V₂O₅ doped Mg₂TiO₄ ceramics

Bhuyan¹,

Kumar²,

Pamu³

et al. 2014

mat express

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“…To date, researchers have identified a number of mechanisms that can cause microwave loss in dielectrics, including free carrier and polaron absorption, EPR, anharmonic‐phonons, and precession of electric dipoles in polar molecules …”

Section: Introductionmentioning

confidence: 99%

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

2015

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Microwave resonator measurements were performed on high‐performance microwave ceramics Ba(Zn1/3Ta2/3)O3 (BZT) and Ba(Zn1/3Nb2/3)O3 (BZN) containing additives commonly used by commercial manufacturers (i.e., Co, Mn, and Ni). We find that the loss tangent, even in ambient magnetic fields, is dominated by electron paramagnetic resonance (EPR) absorption by exchange‐coupled 3d electrons in transition metal clusters at cryogenic temperatures. The large orbital angular momentum in Co2+ and Ni2+ ions of L = 3 causes strong anisotropic‐broadened dipolar interactions that extend EPR losses to zero applied field. This effect is greatest in BZN with Co concentrations greater than 0.5 mol%, dominating the losses at liquid nitrogen temperatures (77 K) and below. In samples containing Mn2+ ions with L = 0, the dipolar interactions and associated EPR losses in ambient fields are smaller. We show the magnetic‐field‐dependent changes in the EPR losses (i.e., tan δ) and magnetic reactive response (i.e., μr) are from the same mechanism, as they follow the Kramers–Kronig relation. Finally, we note that these materials can make ultra‐high Q passive microwave devices with externally controlled transfer functions, as the quality factor (Q) of the composition Ba(Co1/15Zn4/15Nb2/3)O3 at 77 K can be tuned from 1 100 to 12 000 at 10 GHz by applying practical magnetic fields.

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“…Recently, SrRAlO 4 (R=La, Nd, Sm) ceramics with K 2 NiF 4 layered structure and I4/mmm space group have been put forward as candidates of ultra-low loss microwave dielectric materials for high-band microwave application [3,4]. Compared with the typical high-Q microwave dielectric ceramics such as Ba(Mg 1/3 Ta 2/3 )O 3 [5], Ba(Zn 1/3 Ta 2/3 )O 3 [6], and Ba(Zn 1/3 Nb 2/3 )O 3 [7], SrRAlO 4 without noble elements such as Ta and Nb have the merits of relative low cost combined with its easier preparation. SrRAlO 4 (R=La, Nd, Sm) layered structure is composed by one perovskite layer (AlO 2 ) alternating with two rock salt layer ((Sr,R)O) and they can be viewed as two kinds of c h a r g e d l a y e r s : − A l O 2 -( S r , R ) O -( S r , R ) OAlO 2 -(Sr,R)O-(Sr,R)O-alternately stacking along the c-axis [8].…”

Section: Introductionmentioning

confidence: 99%

Structure and microwave dielectric properties of SrSmAlO4-Sr2TiO4 solid solutions

Liu

et al. 2014

J Electroceram

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The structure and microwave dielectric properties of Sr 1+x Sm 1-x Al 1-x Ti x O 4 ceramics were determined in the entire composition range of x=0~1.0. The single phase solid solutions with K 2 NiF 4 structure were obtained, and the Q×f value decreased with increasing x at first (up to 0.15) and then turned to increase and reached the maximum at x=0.9. The dielectric constant ε r increased from 19.2 to 36.5 and the temperature coefficient of resonant frequency τ f ascended monotonously with increasing x. The variation tendency of Q×f value with x reflected the competition result of the interlayer polarization and the structure inhomogeneity. On the other hand, infrared (IR) reflectivity spectra were measured and fitted by means of classical oscillator model simulation. The intrinsic dielectric loss tangent extrapolated from IR range showed a similar changing trend with the measured ones. Moreover, the fitting results offered a detail inside view of the intrinsic factors and the variation of the dielectric loss could be well explained.

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Temperature and frequency dependence of dielectric loss of Ba(Mg1/3Ta2/3)O3 microwave ceramics

Cited by 17 publications

References 9 publications

Low temperature and broadband dielectric properties of V₂O₅ doped Mg₂TiO₄ ceramics

Low temperature and broadband dielectric properties of V₂O₅ doped Mg₂TiO₄ ceramics

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

Structure and microwave dielectric properties of SrSmAlO4-Sr2TiO4 solid solutions

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Temperature and frequency dependence of dielectric loss of Ba(Mg1/3Ta2/3)O3 microwave ceramics

Cited by 17 publications

References 9 publications

Low temperature and broadband dielectric properties of V2O5 doped Mg2TiO4 ceramics

Low temperature and broadband dielectric properties of V2O5 doped Mg2TiO4 ceramics

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn1/3Ta2/3)O3 and Ba(Zn1/3Nb2/3)O3 at Cryogenic Temperatures

Structure and microwave dielectric properties of SrSmAlO4-Sr2TiO4 solid solutions

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Low temperature and broadband dielectric properties of V₂O₅ doped Mg₂TiO₄ ceramics

Low temperature and broadband dielectric properties of V₂O₅ doped Mg₂TiO₄ ceramics

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures