Creating Ioffe-Pritchard micro-traps from permanent magnetic film with in-plane magnetization

We present designs for Ioffe-Pritchard type magnetic traps using planar patterns of hard magnetic material. Two designs are based on 40 μm foil of FePt. The first sample yields calculated axial and radial trap frequencies of 51 Hz and 6.8 kHz, respectively. For the second sample the calculated frequencies are 34 Hz and 11 kHz. The structures were produced by spark erosion and used successfully as a magneto-optical trap and loaded as a magnetic trap. A third design is based on lithographically patterned 250 nm film of FePt on a Si substrate and yields an array of 19 traps with calculated axial and radial trap frequencies of 1.5 and 110 kHz, respectively.