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This paper presents a distributed magnetic sensing system for continuous magnetic profile measurement along the entire length of a sensor cable. Our sensor includes novel features such as: (1) coaxial cable with a bundle of magnetic wires as an inner conductor for inducing a magneto-impedance (MI) effect, (2) reflected wave from the characteristic impedance unmatching region, and (3) monitoring the position and strength of the magnetic field with time-domain reflectometry (TDR). This paper reports the principle of magnetic fiber sensing, position identification with distance resolution of 10 mm, and a sensor sensitivity of 53 µV/µT by using a bias magnetic field.

The piezoresistivity is a change in the electrical resistivity of a semiconductor when mechanical stress is applied. A number of studies of the polycrystalline diamond (PCD) piezoresistivity have been reported before. And it was examined that the shear piezoresistive coefficients in single crystalline Silicon (Si) and Germanium (Ge) are exceptionally large due to its crystal orientation anisotropy. However, the single crystalline diamond (SCD) piezoresistivity has been rarely investigated with respect to crystal orientation anisotropy. In this study, the piezoresistive coefficients π11, π12 and π44 of SCD were measured experimentally with the SCD piezoresistors fabricated from the boron (B)-doped SCD thin films. It was found that the coefficient π44 of SCD at 4.5 ppm B/C ratio were 18.3 and 12.0 times as large as the coefficient π11 of that and the coefficient π44 of PCD, respectively.