Dielectric Properties of Ti-doped K(Ta, Nb)O₃ Thin Films for Tunable Microwave Applications

Ferroelectric materials have been widely investigated for high density dynamic random access memories, opto-electrics, and tunable microwave devices due to their properties. In this study, we have investigated the dielectric properties of Ti doped K(Ta, Nb)O₃ thin films. By doping Ti into the K(Ta,Nb)O₃ system, Ti with a valence value of +4 will substitute Ta or Nb ions with a valence value of +5. This substitution will introduce an acceptor state. Therefore, this introduced acceptor state will reduce dielectric loss by trapping electrons. Using 3% Ti-doped K(Ta,Nb)O₃ targets, K(Ta,Nb) 03:Ti films were grown in MgO(001) crystals using pulsed laser deposition. First, growth conditions were optimized. A reduction in the loss tangent was observed for Ti-doped K(Ta,Nb)O₃ relative to undoped films, although a reduction in tunability is also seen. The crystallinity, morphology, and tunability of K(Ta,Nb)O₃:Ti films are reported.

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