An electro-chemical magnetic field sensor

We have presented some results of the investigation of extreme large value of the electrode potential (EP) for the ferromagnetic electrodes in the ext ernal magnetic field. The measured EP value is about 20 mV for the Fe-elect rode in the magnetic field of 3 kOe, which is three orders of magnitude lar ger in comparison with the theoretical estimation. The issues presented are as follows: the EP dependencies on the magnetic field for electrodes from various ferromagnetic (Fe and Ni) and paramagnetic (Cu) metals and EP depen dencies on the magnetic field for the various types and concentration of el ectrolytes (FeCl3 and H2SO4). A very significant EP hysteresis and strong E P relaxation for ferromagnetic electrodes have been found and the correlati on between them has been discussed. The EP relaxation is measured at differ ent rates of the magnetic field variation and the long-time character of re laxation is observed. The width of EP hysteresis loop strongly depends on t he magnetic field orientation relatively to the electrode plane. This fact can be considered as the evidence of the correlation between the EP and the magnetic state of the electrode. This effect can be used either for the de finition of the magnetic state of the electrode as well as for measuring th e external magnetic field. A model sensor for measuring the magnetic field is proposed. (C) 2000 Elsevier Science S.A. All rights reserved.