Near Zero-Field Magnetoresistance and High and Ultra Low Frequency Electrically Detected Magnetic Resonance in 4H-SiC p-n Junctions*

We have investigated 4H-SiC p-n junction diodes with X-band (~10GHz) and ultra-low frequency (~10MHz) electrically detected magnetic resonance (EDMR) and compared the EDMR response to the near zero-field magnetoresistance (MR) of these devices. Both the EDMR and the MR involve spin-dependent recombination within the junction depletion region. These measurements were made over a wide range of junction forward bias. The EDMR measurements involve current change via resonance induced changes in triplets to singlets, whereas MR involves singlet – triplet mixing. The study involves several devices with significantly different doping. The EDMR and MR comparisons provide some physical insight into the MR. Development of a fundamental understanding of the near-zero field MR may be of real technological significance as the response can be exploited in a new class of magnetometers designed for deep space applications.

C.J. Cochrane et al. Scientific Nature: Science Reports, vol. 6, 37077 (2016)