Magnetic Shape Memory alloy based Fiber Bragg Grating magnetic field sensor

The paper discusses a new device for magnetic field sensing, based on the integration of a fiber Bragg grating (FBG) with a magnetic shape memory alloy (MSMA). The latter is a new kind of material able to show extremely large strains in response to a magnetic field. Differently from classical shape memory alloys (SMA), actuated by temperature, they normally show quite fast responses. In the paper the basic features of the proposed device are illustrated and field range and sensitivity of the device are also discussed. Moreover, comparison with Terfenol based FBG sensor performances is reported showing for MSM based one a sensitivity expressed as (Deltalambda_B/lambda_B)/(DeltaH/H_m) of 1.81ldr10^-4 , where lambda_B is the Bragg wavelength and H_m the mean magnetic field in the considered range.