Samsung NX500 has a 28.0MP APS-C (23.5 x 15.7 mm ) sized BSI-CMOS sensor and features DRIMe 5 processor. On the other hand, Sony A6000 has a 24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz X processor.
Another difference between these two cameras is that Samsung NX500's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the NX500 and A6000 sensor size comparison.
Samsung NX500 and Sony A6000 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.