Manipulation of free-layer bias field in giant-magnetoresistance spin valve by controlling pinned-layer thickness

The giant magnetoresistance (GMR) effect in FeMn/NiCoFe/Cu/NiCoFe spin valve prepared by dc opposed target magnetron sputtering is reported. The spin valve thin films are characterized by Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM) and magnetoresistance ratio measurements. All measurements are performed in room temperature. The inserted 45 mm thickness FeMn layer to the NiCoFe/Cu/NiCoFe system can increase the GMR ratio up to 32.5%. The coercive field to be increased is compared with different FeMn layer thickness. Furthermore, the coercive field (Hc) decreases with increasing FeMn layer thickness. Magnitude of coercive field is 0.1 T, 0.09 T and 0.08 T for FeMn layer thickness is 30 nm, 45 nm and 60 nm, respectively. The FeMn layer is used to lock the magnetization in the ferromagnetic layer through the exchange anisotropy. This paper will describe the development of a GMR spin valve and its magnetic properties.

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Insertion of a Specular Reflective and Transmissive Nano-Oxide Layer into Giant Magnetoresistance Spin-Valve Structure

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2006.17965 ◽

2006 ◽

Vol 6 (11) ◽

pp. 3483-3486

Author(s):

Chunghee Nam ◽

Youngman Jang ◽

Ki-Su Lee ◽

Jungjin Shim ◽

B. K. Cho

Keyword(s):

Oxide Layer ◽

Sheet Resistance ◽

Giant Magnetoresistance ◽

Spin Valve ◽

Interlayer Coupling ◽

Free Layer ◽

Uniform Layer ◽

Nano Oxide ◽

Valve Structure ◽

Current Shunt

We have studied the influence of the insertion of a nano-oxide layer (NOL) into a magnetic GMR spin-valve. It was found that the spin-valve with NOL has a higher GMR ratio than that of the normal spin-valve without NOL. Naturally formed NOL without vacuum break shows a uniform layer, which effectively suppresses the current shunt, resulting in the reduction of the sheet resistance of GMR. The NOL spin-valve also shows a lower interlayer coupling (Hin) than that of the optimal normal spin-valve, which is consistent with AFM measurement showing lower roughness of NOL formed CoFe surface. Based on the advantage of NOL, we succeeded in lowering Hin while maintaining GMR ratio by insertion of NOL inside the CoFe free layer, where the free layer consists of CoFe/NOL/CoFe/NOL/Capping layer.

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Perpendicular giant magnetoresistance and magnetic switching properties of a single spin valve with a synthetic antiferromagnet as a free layer

Physical Review B ◽

10.1103/physrevb.68.224426 ◽

2003 ◽

Vol 68 (22) ◽

Cited By ~ 14

Author(s):

Y. Jiang ◽

S. Abe ◽

T. Nozaki ◽

N. Tezuka ◽

K. Inomata

Keyword(s):

Giant Magnetoresistance ◽

Spin Valve ◽

Free Layer ◽

Single Spin ◽

Synthetic Antiferromagnet ◽

Magnetic Switching

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Analisa Magnetoresistance Berbasis Lapisan Tipis Giant Magnetoresistance (GMR) Pada Nanopartikel Cobalt Ferrite (CoFe2O4) Dilapisi Polyethylen Glicol (PEG)

Jurnal Fisika Indonesia ◽

10.22146/jfi.27955 ◽

2017 ◽

Vol 20 (1) ◽

pp. 6

Author(s):

Novi Susanti ◽

Edi Suharyadi

Keyword(s):

Giant Magnetoresistance ◽

Cobalt Ferrite ◽

Spin Valve ◽

Probe Method ◽

Free Layer

Telah dilakukan pengukuran magnetoresistance pada lapisan tipis spin valve GMR yang memiliki struktur CoFeB/Cu/CoFe/MnIr dengan memvariasikan ketebalan lapisan barrier Cu (2,2 dan 2,8 nm) dan free layer CoFeB (7 dan 10 nm) menggunakan System Four Point Probe Method (SFPPM) pada medan eksternal 0 600 gauss. Dihasilkan perubahan range resistansi (69,29-71,74) Ω untuk Cu 2,2 nm dan (38,5-40,47) Ω untuk ketebalan Cu 2,8 nm. Pada variasi ketebalan CoFeB dihasilkan perubahan range resistansi untuk ketebalan 7 nm dan 10 nm masing masing adalah (38,74-41,11) Ω dan (69,29-71,74) Ω. Selanjutnya lapisan tipis digunakan sebagai sensor magnetik untuk mendeteksi kehadiran nanopartikel CoFe2O4, CoFe2O4 yang dimodifikasi PEG dan CoFe2O4 termodifikasi PEG yang telah mengikat biomolekul formalin. Terjadi pergeseran nilai resistansi ketika lapisan tipis dilapisi nanopartikel magnetik tersebut. Hal ini menunjukkan bahwa lapisan tipis GMR mampu mendeteksi prilaku spin pada nanopartikel magnetik CoFe2O4.

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