An important application of the Néel effect is as a current sensor, measuring the magnetic field radiated by a conductor with a current; this is the principle of Néel effect current sensors. The Néel effect allows the accurate measurement of currents with very low-frequency-type sensors in a current transformer without contact.
The transducer of a Néel-effect current sensor consists of a coil with a core of superparamagnetic nanoparticles. The coil is traversed by a current excitation:
In the presence of an external magnetic field to be measured: 
the transducer transposes (with the Néel effect) the information to be measured, H (f) around a carrier frequency, the harmonic of order 2 excitation current 2:
which is simpler. The electromotive force generated by the coil is proportional to the magnetic field to measure:
and to the square of the excitation current:
To improve the measurement's performance (such as linearity and sensitivity to temperature and vibration), the sensor includes a second permanent winding-reaction against it to cancel the second harmonic. The relationship of the current reaction against the primary current is proportional to the number of turns against reaction: