Review of Magnetic Resonance Force Sensors Based on Nanomechanical Cantilever

Abstract

Three-dimensional force distribution based on magnetic resonance in microsamples can be obtained by Si nanomechanical cantilevers with a magnet. Highly sensitive magnetic sensors require operation under high-Q, high-vacuum conditions. To overcome the limitation of operation in vacuum conditions, a force sensor for magnetic resonance detection with a vacuum-sealed magnetic cantilevers was developed. A silicon-based cantilever with a magnet particle was enclosed in a vacuum chamber using anodic-bonding and direct metal (Sn-Al) bonding. The proposed vacuum sealed magnet-based cantilever has confirmed the high feasibility of magnetic resonance force detection within a non-hermetic environment. The fabrication process of mounting the magnets one by one is undesirable in terms of manufacturing cost. Compared to other deposition methods, the electroplating method of magnetic material can produce thicker magnetic films and lower production costs. On the other hand, force detection with sensors with high Q-factor has a long response time. In order to reduce the measurement time, we proposed a two-dimensional force transducer with Si thin wires assembled on a glass trench and a bridge resonator including a field-effect transistor.