Diamagnetic Levitation of Solids at Microscale

Abstract

Friction and stiction problems often occur in microsensors and microactuators. An original solution proposed here consists in diamagnetic levitation above integrated micromagnets. This static, energy free, room temperature levitation is seldom used because of the weakness of the forces involved. However, scale reduction enhances diamagnetic volume forces. Therefore, levitation is easily obtained at the microscale. In this work, the levitation of a microparticle of bismuth is studied. Static and dynamic simulations are presented and confronted to experiments. The static simulations enable one to find the location and to quantify the stability of levitation. Dynamic simulations are required to fully explain the results of the experiments proposed. The structure is then fabricated and successful levitation of bismuth in air and copper and silicon in paramagnetic water is reported. Applications in material conveyance, inertial sensors such as inclinometer or accelerometer are explored.