Electrical detection of a skyrmion in a magnetic tunneling junction*

A magnetic skyrmion, the swirling spin texture in magnets, is expected to be a future information carrier. Many efforts, such as creation/deletion, control, and detection, are made to implement skyrmions into devices, however, the detection seems to be much difficult. In this study, we investigated the magnetoresistance (TMR) ratio in the 2 dimensional skyrmion/ferromagnet bilayer system using the tunneling Hamiltonian approach and the double exchange model. As a result, we show that the TMR ratio can be larger than 30%, which is determined sorely by the spin profile of the skyrmion, if only the spectral broadening is smaller than the exchange coupling strength. This criterion is quite simple and easily achievable in many realistic systems, therefore the magnetic tunneling junction geometry is shown to be a good candidate for the readout part of the future skyrmionics memory devices.