Magnetic field sensor having nickel oxide and cobalt containing ferromagnetic layers
AssigneeU.S. Philips Corporation
InventorJacques C. S. Kools
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Abstract
A magnetic field sensor comprising a layered structure (3) E/Fo/S/F, in which: E is an exchange-biasing layer, comprising nickel oxide; Fo is a ferromagnetic layer with a fixed magnetization, comprising cobalt; S is a spacer layer; Ff is a ferromagnetic layer with a free magnetization, whereby the material of the layer Ff has a magnetostriction constant of at most 1.5×10−6 and a crystal anisotropy of at most 1.3 J/m3. Such a structure (3) demonstrates a relatively high magneto-resistance ratio (of the order of 15%), and yet a relatively low coercivity (of the order of 0.2 kA/m). Examples of suitable materials for use in the layer Ff include Ni66Fe16Co18 and Ni72Fe21Co7.
Claims8
A magnetic field sensor comprising a layered structure E/Fo/S/Ff, in which:
- E is an exchange-biasing layer, comprising nickel oxide;
- Fo is a ferromagnetic layer with a fixed magnetization, comprising cobalt;
- S is a spacer layer;
- Ff is a ferromagnetic layer with a free magnetization, characterized in that the material of the layer Ff has a magnetostriction constant of at most 1.5×10−6 and a crystal anisotropy of at most 1.3 J/m3.
Dependencies are inferred from the claim text.