When the MRF wholly yields, the angular velocity of MRF increases nonlinearly with its radius, the non-linear distribution becomes more obvious as the magnetic intensity in the working gap increases.

Like synchronous motor, rotor magnetic pole center line could lagged behind an Angle of that of air-gap magnetic field under the function of load torque (called angular displacement).

This competition leads to high angular sensitivity in response to the refractive index variation of the sample solution in the gap.