Electrically and magnetically tunable microwave device using (Ba, Sr) TiO3/Y3FeO12 multilayer

Ferroelectric (Ba0.6Sr0.4)TiO3 (BST) thin films have been deposited by puls ed laser deposition onto single-crystal Y3Fe5O12 (YIG) substrates with/with out a MgO buffer layer. The structure and microwave properties of the BST f ilms have been investigated as a function of substrate orientation and O-2 deposition pressures (50-800 mTorr). The crystallographic orientation of BS T film varies with the deposition conditions. The dielectric properties of the ferroelectric were measured using interdigitated capacitors deposited o n top of the BST film. BST films exhibit high tunability (20%-40%) and high dielectric Q = 1/tan delta (30-50) with a de bias field of 67 kV/cm at 10 GHz. A coplanar waveguide transmission line was fabricated from a (001)-ori ented BST film on (111)YIG which exhibited a 17 degrees differential phase shift with an applied de bias field of 21 kV/cm (10 GHz). An equivalent dif ferential phase shift was achieved with a magnetic field of 160 Gauss, PACS : 81.15.Fg; 84.40. Lj; 77.84.Dy.