The invention relates to a releasable stud for a shoe sole. The identifier can be received from a first device that utilizes a first communication protocol and the target device can utilize a second communication protocol. The isolation layer pattern extends in a second direction. The concentration of Al in the AlXN layer, the AlXN layer thickness and the n-doping concentration in the n-doped GaN layer are selected to induce a 2DEG charge in channel access regions without inducing any substantial 2DEG charge beneath the gate, so that the channel is not conductive in the absence of a switching voltage applied to the gate. Heating for the AFM to FM transition is provided by write coils andor a coil located near the AFM-FM phase change material to enable faster transition times.