Dielectric material, device including the same, and method of preparing the dielectric material
A dielectric material, a device including the same, and a method of preparing the dielectric material are provided. The dielectric material may include a compound represented by the following Formula 1: K 1+x NaSr 4-2x La x Nb 10 O 30 , Formula 1 wherein, in Formula 1, 0<x<2.
1 . A dielectric material comprising:
a compound represented by Formula 1:
K 1+x NaSr 4-2x La x Nb 10 O 30 , Formula 1
wherein 0<x<2.
2 . The dielectric material of claim 1 , wherein 0<x≤1.
3 . The dielectric material of claim 1 , wherein 0<x≤0.5.
4 . The dielectric material of claim 1 , wherein the compound includes a tungsten-bronze crystal structure.
5 . The dielectric material of claim 1 , wherein the compound includes
a tungsten-bronze crystal structure of KNaSr 4 Nb 10 O 30 , and
a structure in which a Sr cation located in an A site in a unit lattice of the KNaSr 4 Nb 10 O 30 is substituted with La 3+ as a donor and K +1 as an acceptor.
6 . The dielectric material of claim 1 , wherein the compound has a tetragonal crystal structure.
7 . The dielectric material of claim 1 , wherein a size of a unit lattice of the compound is increased compared to a size of a unit lattice of KNaSr 4 Nb 10 O 30 .
8 . The dielectric material of claim 1 , wherein
the compound includes at least one of K 1.01 NaSr 3.98 La 0.01 Nb 10 O 30 , K 1.05 NaSr 3.9 La 0.05 Nb 10 O 30 , K 1.1 NaSr 3.8 La 0.1 Nb 10 O 30 , K 1.15 NaSr 3.7 La 0.15 Nb 10 O 30 , K 1.2 NaSr 3.6 La 0.2 Nb 10 O 30 , K 1.25 NaSr 3.5 La 0.25 Nb 10 O 30 , K 1.3 NaSr 3.4 La 0.3 Nb 10 O 30 , K 1.35 NaSr 3.3 La 0.35 Nb 10 O 30 , K 1.4 NaSr 3.2 La 0.4 Nb 10 O 30 , K 1.45 NaSr 3.1 La 0.45 Nb 10 O 30 , K 1.5 NaSr 3 La 0.5 Nb 10 O 30 , K 1.55 NaSr 2.9 La 0.55 Nb 10 O 30 , K 1.6 NaSr 2.8 La 0.6 Nb 10 O 30 , K 1.65 NaSr 2.7 La 0.65 Nb 10 O 30 , K 1.7 NaSr 2.6 La 0.7 Nb 10 O 30 , K 1.75 NaSr 2.5 La 0.75 Nb 10 O 30 , K 1.8 NaSr 2.4 La 0.8 Nb 10 O 30 , K 1.85 NaSr 2.3 La 0.85 Nb 10 O 30 , K 1.9 NaSr 2.2 La 0.9 Nb 10 O 30 , K 1.95 NaSr 2.1 La 0.95 Nb 10 O 30 , K 2 NaSr 2 LaNb 10 O 30 , K 2.05 NaSr 1.9 La 1.05 Nb 10 O 30 , K 2.1 NaSr 1.8 La 1.1 Nb 10 O 30 , K 2.15 NaSr 1.7 La 1.15 Nb 10 O 30 , K 2.2 NaSr 1.6 La 1.2 Nb 10 O 30 , or K 2.25 NaSr 1.8 La 1.25 Nb 10 O 30 .
9 . The dielectric material of claim 1 , wherein an electric field-polarization graph of the dielectric material has a linear curve shape in which, as an amount of La is increased, residual polarization (Pr) is reduced and in which the polarization is proportional to an applied electric field.
10 . The dielectric material of claim 1 , wherein a maximum permittivity of the dielectric material, at 1 kHz, is within a range of 1,000 to 2,600.
11 . The dielectric material of claim 1 , wherein in a graph showing changes in permittivity according to temperature of the dielectric material, as an amount of La is increased, a temperature (T max ) at which the dielectric material has maximum permittivity is decreased.
12 . The dielectric material of claim 1 , wherein
the dielectric material is a solid solution including polar nano regions (PNR).
13 . The dielectric material of claim 12 , wherein
the PNR include defect clusters in which a Sr cation located in an A site in a unit lattice of KNaSr 4 Nb 10 O 30 is substituted with La 3+ as a donor, and K +1 as an acceptor.
14 . A device comprising:
a plurality of electrodes; and
at least one dielectric layer between the plurality of electrodes, the at least one dielectric layer including the dielectric material of claim 1 .
15 . The device of claim 14 , wherein
the device is a multi-layered capacitor,
the plurality of electrodes includes a plurality of internal electrodes,
the at least one dielectric layer includes dielectric layers alternately arranged between the plurality of internal electrodes.
16 . The device of claim 15 , wherein a main component of the plurality of internal electrodes is nickel.
17 . The device of claim 14 , wherein a maximum permittivity of the at least one dielectric layer, at 1 kHz, is within a range of 1,000 to 2,600.
18 . The device of claim 14 , wherein a resistivity of the at least one dielectric layer is within a range of 1.0 E+11 Ωcm to 1.0 E+14 Ωcm.
19 . The device of claim 14 , wherein an effective permittivity of the at least one dielectric layer at room temperature and 125° C. when 8.7 V/μm of DC bias is applied is within a range of 1,000 to 1,150.
20 . An electronic device comprising:
a capacitor; and
a transistor,
wherein at least one of the capacitor or the transistor includes the device of claim 14 .
21 . A method of manufacturing a dielectric material, the method comprising:
mechanically milling a mixture of potassium salts, sodium salts, strontium salts, niobium compounds, and lanthanum compounds; and
heat-treating the mixture under an oxidizing atmosphere,
wherein the dielectric material includes a compound represented by the following Formula 1
K 1+x NaSr 4-2x La x Nb 10 O 30 , Formula 1
wherein 0<x<2.
22 . The method of claim 21 , wherein the heat-treating is performed within a range of 900° C. to 1,200° C.
23 . The method of claim 21 , further comprising:
obtaining a molded article by molding a product of the heat-treating; and
performing a second heat-treatment on the molded article.
24 . The method of claim 23 , wherein the second heat-treatment is performed within a range of 1,200° C. to 1,500° C.
25 . The method of claim 21 , wherein the heat-treating the mixture oxidizes the mixture.