Magnetic Field Enhancement with Soft Magnetic Flux Guides
In this work, a study of the sensitivity enhancement of spin valve sensors, when located in close proximity to magnetic flux guides, is presented. The magnetoresistance (MR) of spin-valve sensors, lithographically patterned into stripes with lateral dimensions, (length) l = 500 µm, (width) wsensor = 1, 2, 6 µm and placed near one/two Co93.5Zr2.8Nb3.7 (CZN) magnetic flux guide, is characterized at room temperature. CZN has a high permeability that together with a defined microstructured shape, is able to concentrate the magnetic flux in a small area, leading to an increase in sensor's sensitivity. The magnetic field amplification is estimated by comparison of sensor sensitivity with/without magnetic flux guides, in the linear operation range, and studied as a function of different parameters. Besides an enhancement in sensitivity, sensors also exhibit an important increase in the hard axis coercivity and a shift from MR(H=0) = 0.5, both attributed to the magnetic flux guides. Amplification factors of the order of 20 are observed..
António Torres Marques, António Fernando Silva, António Paulo Monteiro Baptista, Carlos Sá, Fernando Jorge Lino Alves, Luís Filipe Malheiros and Manuel Vieira
D.C. Leitão et al., "Magnetic Field Enhancement with Soft Magnetic Flux Guides", Materials Science Forum, Vols. 587-588, pp. 313-317, 2008