A single-phase novel green phosphor Sr2Y3(SiO4)2(PO4)O2:Eu2+ with apatite structure was obtained for the first time.

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Extensive research is currently being conducted on the integration of inductors and capacitors in impedance matching networks, LC-tanks, filters, and other applications in radio-frequency (RF) silicon technology. Tunability of these RF passive components is highly desirable, as it gives the circuit designer the possibility to adjust to the optimum circuit operation at all termination conditions. While electrically tunable capacitors (varactors) have been used for quite some time, work on tunable inductors is leaping far behind. The excessive chip-area consumption of integrated RF inductors not only raised the unit cost, but also degrades the performance of the circuit because of the cross-talk through, and losses in the silicon substrate. Recent progress has been made using two approaches: a MEMS based approach in which the inductor core is moved by a micromachined electromechanical actuator [1], [2] and a solid state approach in which the core permeability is changed by saturation with a dc magnetic field [3]. Both approaches have their limitations. The MEMS process requires a relatively large chip area, involves an expensive and complex manufacturing process and provides only a small tuning range. The approach using a saturable magnetic core will prove problematic as further miniaturization of this device. It becomes difficult to fabricate efficient, tightly wound thin film coils and the reduced volume of the core will introduce excessive Barkhausen noise due to magnetic domains. We proposed a novel mechanism by which to modulate the permeability of a magnetic core. Our analysis has shown that a current passing through a coupled magnetic bi-layer called a synthetic antiferromagnet (SAF) can change its effective permeability over a wide range.A key advantage of this mechanism is that SAF layers are resistant to magnetic domain formation and thus will allow high quality, low noise devices in small form factors. In addition, the use of the proposed SAF structure in place of the core eliminates the need for additional external windings by exploiting the internal current for permeability modulation. Such an electrically modulated magnetic core could be produced by a single lithography step in a typical thin film process. In order to advance this concept, we seek to investigate, theoretically and experimentally, the magnetic behavior of this structure in response to external fields as well as fields generated by internal currents. The electrically tunable magnetic device considered here is a magnetic thin film bilayer consisting of two ferromagnetic films (e.g. NiFe) coupled through an intervening nonmagnetic spacer layer (e.g. Cu). Various magnetic phases which such structure can produce were outlined by Worledge [4]. We extended this work by including the effect of internal current to investigate the current modulated susceptibility using a simple energy model. Description of the magnetization behavior in this coupled bilayers takes into account the effect of thickness (t), width (w), magnetization (Ms), induced an...