Demonstration of Kirchhoff's First Law for Pure Spin Currents

In conventional electronics a fundamental component of circuit design is the principle of fan-out, which allows multiple operations to be performed in order to build up complex logical procedures. A fan-out device relies on the condition that electrical currents obey Kirchoff's laws and in order for spin-logic to be viable, the same must be shown for pure spin currents. Both fan-out and fan-in experiments have been performed to observe how spin currents behave in a multi-terminal circuit. The development of a 3-dimensional nonlocal IV and matrix fitting method provides information about each spin current, along with the thermal current generated at the injection point, and how they interact with each other. The fan-out geometry demonstrates that a pure spin current will divide between the different branches in a circuit, with a magnitude determined through the spin resistances of each arm. The fan-in measurements demonstrate that two pure spin currents will add and subtract with each other in a conventional manner expected from Kirchhoff's first law. These experiments have demonstrated the symmetry of pure spin currents with respect to the injection current and shown that they obey Kirchhoff's current law.