Spin torque nano-oscillator achieved with point contact current injection

Spin torque devices can be used to generate microwave signals without capacitors and resistors normally required by traditional circuits, making such devices ideal in nanoelectronic designs. The limited power output (<5nW) of a single spin torque device makes it necessary to connect multiple devices in parallel to achieve a desired power level. The size of each individual spin torque nano-oscillator (STNO) is therefore critical to many proposed applications that depend on using a large array of such device. Instead of directly fabricating devices at tens of nanometers in diameter, we successfully achieve the behavior of a 50 nm STNO using a current injected through a point contact to the top layer of a much larger (~500 nm), in-plane magnetized device. The point contact is achieved with a conductive AFM tip. This result provides evidence that patterning with mechanical indentation, which creates point contacts at a similar size, is a possible way to fabricate STNO arrays.