Microwave Dielectric Loss of Titanium Oxide
Microwave Dielectric Loss of Titanium Oxide
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DOI：
10.1111/j.1151-2916.2000.tb01154.x
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发表时间：
2000
影响因子：
3.9
通讯作者：
A. Templeton;Xiaoru Wang;S. Penn;S. Webb;L. Cohen;N. Alford
中科院分区：
文献类型：
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作者：
A. Templeton;Xiaoru Wang;S. Penn;S. Webb;L. Cohen;N. Alford
在 3 GHz 频率下测量了二氧化钛 (TiO2) 圆盘的介电损耗 (tan δ)。烧结至几乎全密度的高纯度 TiO2 表现出非常高的 tanδ，这被解释为由于缺氧所致。为了解决这个问题，掺杂稳定的二价和三价阳离子（例如 Mg 和 Al）可能会导致低 tan δ，这可能是通过防止 Ti4+ 还原来实现的。掺杂二价和三价离子的多晶 TiO2 的 tan δ 在 3 GHz 时离子半径在 0.5–0.95 A 范围内，可以非常低：在 300 K 温度下为 6 × 10−5 (Q∼ 17 000)。当圆盘从 300 K 冷却到 ∼100 K 时，未掺杂的纯 TiO2 圆盘的 tan δ 会增加。 <100 K，tanδ 迅速减小，这被解释为载流子冻结。所有高 Q 掺杂 TiO2 多晶样品的 tan δ 在 15 K 时平稳降低至 ∼5 × 10−6 (Q∼ 200 000)，与单晶相当。
The dielectric loss (tan δ) of titanium dioxide (TiO2) disks has been measured at a frequency of 3 GHz. High-purity TiO2 sintered to almost-full density exhibits a very high tan δ, which is interpreted to be due to oxygen deficiency. To counter this, doping with stable divalent and trivalent cations, such as Mg and Al, leads to a low tan δ, probably by preventing Ti4+ reduction. The tan δ of polycrystalline TiO2 doped with divalent and trivalent ions with ionic radii in the range of 0.5–0.95 A at 3 GHz can be very low: 6 × 10−5 (Q∼ 17 000) at a temperature of 300 K. The tan δ of undoped pure TiO2 disks increases when the disks are cooled from 300 K to ∼100 K. At temperatures <100 K, the tan δ decreases rapidly, which is interpreted as carrier freeze-out. The tan δ for all the high-Q doped TiO2 polycrystalline samples smoothly decrease to ∼5 × 10−6 (Q∼ 200 000) at 15 K, comparable to that of single crystals.