Low-frequency dielectric constants of α-quartz, sapphire, MgF2, and MgO

Fontanella, J. J.; Andeen, Carl; Schuele, D. E.

doi:10.1063/1.1663690

Cited by 116 publications

(39 citation statements)

References 12 publications

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“…3, where ε 0 S c /C is f = 10 Hz. From the slope of the linear fitting, κ MgO is evaluated to be 18.8±3.2, which shows agreement with the reference value (∼10) 21 within a factor of two. The discrepancy may be attributed to the overestimation of C using eq.…”

Section: A Capacitance Measurementsupporting

confidence: 48%

Dielectric and magnetic characterizations of capacitor structures with an ionic liquid/MgO barrier and a ferromagnetic Pt electrode

et al. 2016

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The dielectric and magnetic properties of electric double layer (EDL) capacitor structures with a perpendicularly magnetized Pt/Co/Pt electrode and an insulating cap layer (MgO) are investigated. An electric field is applied through a mixed ionic liquid/MgO barrier to the surface of the top Pt layer, at which the magnetic moment is induced by the ferromagnetic proximity effect. The basic dielectric properties of the EDL capacitor are studied by varying the thickness of the MgO cap layer. The results indicate that the capacitance, i.e., the accumulated charge density at the Pt surface, is reduced with increasing the MgO thickness. From the MgO thickness dependence of the capacitance value, the effective dielectric constant of the ionic liquid is evaluated. Almost no electric field effect on the magnetic moment, the coercivity, or the Curie temperature is confirmed in the top Pt layer with the thickness of 1.3 nm, regardless of the presence or absence of the MgO cap layer, whereas the a clear change in the magnetic moment is observed when the top Pt layer is replaced by a Pd layer of 1.7 nm.

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Section: A Capacitance Measurementsupporting

confidence: 48%

Dielectric and magnetic characterizations of capacitor structures with an ionic liquid/MgO barrier and a ferromagnetic Pt electrode

et al. 2016

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“…23͒ and 11.6. 25 The values of the linewidth ␥(T) at the zone boundary are estimated in terms of the measured ␥(T) at the zone center ͑see Fig. 4͒.…”

Section: Relaxation Frequency ⌫ For Al 2 Omentioning

confidence: 99%

Microwave dielectric loss in oxides: Theory and experiment

Aupi

Breeze

Ljepojevic

et al. 2004

Journal of Applied Physics

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We present a model that provides a description of the microwave dielectric loss in oxides. The dielectric loss ͑tan ␦͒ in single crystal and polycrystalline MgO and Al 2 O 3 is measured over the temperature range 70-300 K. We are able to model the dielectric loss in terms of a two-phonon difference model. There are two key parameters in this model: The third derivative, 3 , of the lattice potential and the linewidth, ␥, of the thermal phonons. In polycrystalline samples, rather than considering the different mechanisms of extrinsic loss, it is assumed that the main effect of extrinsic factors is a modification of the linewidth of the thermal phonons. By varying ␥(T), it is shown that the model can describe the loss in both single crystals and polycrystallines materials. In single crystal and polycrystalline MgO, we use ␥ as a fitting parameter. In single crystal and polycrystalline Al 2 O 3 , we obtain ␥(T) by Raman spectroscopy. The theory gives the right order of magnitude of the measured loss.

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“…anorthite and c~-spodumene (Shannon et al 1992b), beryllonite (Shannon et al 1992a) epidote and zoisite (Shannon et al 1992 d), pyrope garnet (Shannon and Rossman 1992) and a series of melilites (Shannon et al 1992e) have been attributed to the presence of "rattling" cations (Orgel 1958) which are characterized by lower than ideal apparent bond valences (V') of one or more of the cations (O'Keeffe 1989). This effect Bartels et al (1979) Shannon et al (1992e) Fontanella et al (1974) Shannon et al (1991b) Fontanella et al (1974 6.61 Lowndes, Martin (1969) 10. 45 Westphal, Sits (1972) 13.6 Estimated from ion polarizabilities was described by Dunitz and Orgel (1906) as a progressive "loosening of the central cation at the center of its surrounding octahedron to off-center displacements characteristic of ferroelectric and antiferroelectric substances" as the size of the central cation in an octahedron decreases.…”

Section: Resultsmentioning

confidence: 89%

Dielectric constants of topaz, orthoclase and scapolite and the oxide additivity rule

1992

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Abstract.The dielectric constants and dissipation factors of topaz, scapolite and orthoclase were determined at i MHz using a two-terminal method and empirically determined edge corrections. The results are: The deviation (A) between measured dielectric polarizabilities as determined from the Clausius-Mosotti equation and those calculated from the sum of ion polarizabilities according to ~o(mineral)= s for topaz is 2.5%. The large deviations of orthoclase and scapolite from the oxide additivity rule with A=+7.2 and +17.6%, respectively, are attributed to "rattling" K ions in orthoclase and "rattling" (Na, K, Ca) ions and disordered O = and C1-ions in scapolite.

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Low-frequency dielectric constants of α-quartz, sapphire, MgF2, and MgO

Cited by 116 publications

References 12 publications

Dielectric and magnetic characterizations of capacitor structures with an ionic liquid/MgO barrier and a ferromagnetic Pt electrode

Dielectric and magnetic characterizations of capacitor structures with an ionic liquid/MgO barrier and a ferromagnetic Pt electrode

Microwave dielectric loss in oxides: Theory and experiment

Dielectric constants of topaz, orthoclase and scapolite and the oxide additivity rule

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