Low magnetic field sensing using manganite (La0.7Sr0.3MnO3) nanoparticles with optical fiber interferometric approach

Manganites have been in research for few decades due to their extremely high promise in magnetoelectronics applications. These systems show more that 200% magneto-resistance (MR); however, at extremely high applied fields (few Tesla). Low-field sensing has always been a challenge. In this context, manganite La0.7Sr0.3MnO3 (LSMO) has been explored for low field sensing using an optical approach. Polycrystalline LSMO nanoparticles have been coated on the distal end of single mode fiber connected to the 1550 nm optical source and configured in Fabry-Perot interferometric mode. A sensitivity of 91 pm/mT has been observed for applied magnetic fields as low as 2 to 86 mT. Changes in the interferometric pattern in terms of wavelength shift and the power change were observed. The results are closely related to the magnetization changes of LSMO nanoparticles close to the Curie temperature and its effect on the dielectric constant and refractive index, which drives the change in the interference pattern, thereby resulting into fine sensing sensitivity. Manganites for low-field sensing, via an optical approach, in a reliable and repeatable fashion is hence projected.