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In linear arrays of optically probed bismuth-doped iron garnet films, the Faraday rotation signal produced by an external magnetic field is a complex function of film shapes, stacking geometries, optical path length, and insertion losses. Studies of arrayed responsivities under various configurations reveal a proximity coupling effect between ferromagnetic domains of adjacent films, which enhances Faraday rotation by minimizing demagnetization effects at the interfaces. The effect is activated by matching ferromagnetic domain patterns in adjacent films and has resulted in over a twofold improvement in detection sensitivities when the arrays were configured as polarimetric magneto-optic sensors. [ABSTRACT FROM AUTHOR]

Abstract: The temperature and applied-magnetic-field dependence of the second moments of the magnetic-field distributions as measured by μSR for YBCO and BSCCO have been fit for four different intrinsic-field-distribution models (d-wave, 2-fluid, empirical, and BCS). It is found that if a pinning potential becomes important at about 20K, all of the models can fit the data reasonably well. The fits and the associated fitting parameters are presented. [Copyright &y& Elsevier]

In bismuth-doped iron garnets, diamagnetic dilution of Fe with Ga is a well-known method to increase the Faraday rotation response under externally applied magnetic fields. It is found, however, that while this method improves responsivity at larger field strengths, the responsivity under smaller fields (which are more typical in sensing applications) is generally unaffected by Ga doping. The data indicate that the low-field responsivity is limited by anomalous pinning effects in the rotational magnetization process of the ferromagnetic domains. To overcome this, a magnetic bias- ing technique was developed, which enhances responsivity by activating Barkhausen steps in the films to free the domains from their pinning sites. [ABSTRACT FROM AUTHOR]

Bismuth doped iron garnet films were studied in arrayed structures to improve sensitivity in polarimetric magnetic field sensors. The sensitivity gained from the arrayed configuration was found to depend on the ferromagnetic domain geometry of the films. Under small, externally applied fields, films with planar anisotropy yielded an optical modulation depth which increased linearly with the number of crystals in the array. In films with perpendicular anisotropy, linearity and sensitivity were obstructed by a mechanism of optical polarization incoherence which was found to be generated within the magnetic domains. Our results indicate that optimal sensitivity in arrayed configurations requires planar anisotropies, or a direction of laser propagation that is perpendicular to the local domain magnetization. [ABSTRACT FROM AUTHOR]