• Title/Summary/Keyword: 자기저항곡선

Search Result 58, Processing Time 0.019 seconds

Regional Distribution of Isotropy Magnetic Property of Dual-type Giant Magnetoresistance-Spin Valve Multilayer (이중구조 거대자기저항-스핀밸브 박막의 자기등방성 영역분포에 관한 연구)

  • Khajidmaa, Purevdorj;Lee, Sang-Suk
    • Journal of the Korean Magnetics Society
    • /
    • v.23 no.6
    • /
    • pp.193-199
    • /
    • 2013
  • The regional distribution of magnetic isotropy depending on the post annealing condition for the dual-type structure GMR-SV (giant magnetoresistance-spin valve) of NiFe/Cu/NiFe/IrMn/NiFe/Cu/NiFe multilayer was investigated. The rotation of in-plane ferromagnetic layer induced by controlment of the post annealing temperature inside of the vacuum chamber. The magnetoresistive curves of a dual-type IrMn based GMR-SV depending on the direction of the magnetization easy axis of the free layer and the pinned layer are measured by between $0^{\circ}$ and $360^{\circ}$ angles for the applied fields. The optimum annealing temperature having a steady and isotropy magnetic sensitivity of 1.52 %/Oe was $107^{\circ}C$ in the rotational section of $0{\sim}90^{\circ}$. By investigating the switching process of magnetization for an arbitrary measuring direction, the in-plane orthogonal magnetization for the dual-type GMR-SV multilayer can be used by a high sensitive biosensor for detection of magnetized micro-beads.

Magnetoresistance of Buffer/CoFe/Cu/Co Sandwiches (Buffer 층을 갖는 CoFe/ Cu/ Co 샌드위치 박막의 자기저항 특성)

  • 송은영;오미영;김경민;이장로;김미양;김희중;박창만;이상석;황도근
    • Journal of the Korean Magnetics Society
    • /
    • v.7 no.3
    • /
    • pp.146-151
    • /
    • 1997
  • Buffer (t $\AA$)/ CoFe(35$\AA$)/Cu (50$\AA$)/Co (35$\AA$) sandwiches prepared by dc magnetron sputtering on Corning glass substrates using the $Co_{90}Fe_{10}$ and Co layers with different coercivities. Dependence of magnetoresistance on the type and thickness of buffer layers, and on the thickness of Cu and the magnetic layers in buffer/ CoFe/Cu /Co sandwiches were investigated. Magnetoresistance ratio and saturation field $H_s$ increased as thickness of the buffer layer becomes thicker, then decreased smoothly after a maximum value. An improved filed sensitivity was realized with the $Ni_{81}Fe_{19}$ buffer layer.

  • PDF

Analysis of Magnetic Isotropy Property using Magnetoresistance Curve of CoFe/Cu/CoFe/PtMn Multilayer Film (CoFe/Cu/CoFe/PtMn 다층박막의 자기저항 곡선을 이용한 자기 등방성 특성 분석)

  • Choi, Jong-Gu;Kim, Su-Hee;Choi, Sang-Heon;Lee, Sang-Suk;Rhee, Jang-Roh
    • Journal of the Korean Magnetics Society
    • /
    • v.27 no.4
    • /
    • pp.123-128
    • /
    • 2017
  • The magnetic isotropy property from the magnetoresistance (MR) curve and magnetization (MH) loop for the PtMn based spin valve (SV) multilayer films fabricated with different the bottom structure after post-annealing treatment was investigated. The exchange biased coupling field ($H_{ex}$), coercivity ($H_c$), and MR ratio of Glass/Ta(10 nm)/CoFe(6 nm)/Cu(2.5 nm)/CoFe(3 nm)/Ta(4 nm) SV multilayer film without antiferromagnetic PtMn layer are 0 Oe, 25 Oe, and 3.3 %, respectively. MR curve for the Glass/Ta(10 nm)/CoFe(6 nm)/Cu(2.5 nm)/CoFe(3 nm)/PtMn(6 nm)/Ta(4 nm) SV multilayer film showed $H_{ex}=2Oe$, $H_c=316Oe$, and MR (%) = 4.4 % with one butterfly MR curve having by the effect of antiferromagnetic PtMn layer. MR curve for the dualtype Glass/Ta(10 nm)/CoFe(6 nm)/Cu(2.5 nm)/CoFe(3 nm)/PtMn(6 nm)/CoFe(3 nm)/Cu(2.5 nm)/CoFe(6 nm)/Ta(4 nm) SV multilayer film showed $H_c=37.5Oe$ and 386 Oe, MR = 3.5 % and 6.5 % with two butterfly MR curves and square-like hysteresis MH loops. The anisotropy property in CoFe spin valve-PtMn multilayer is neglected by the effects of a very small value of $H_{ex}$ and a very slightly shape magnetic anisotropy. This result is possible to explain the effect of magnetization configuration spin array of the bottom SV film and the top SV film of PtMn layer.

Magnetoresistance effects in [Co/Cu/NiFe/Cu] Spin-valve Multilayers ([Co/Cu/NiFe/Cu] 다층박막의 자기저항효과에 관한 연구)

  • 정진봉;박창만;이기암;황도근;이상석
    • Journal of the Korean Magnetics Society
    • /
    • v.5 no.3
    • /
    • pp.203-209
    • /
    • 1995
  • A study of the dependence of the magnetoresistance in $glass\[Cu_{x\AA}\NiFe_{50\AA}\Cu_{x\AA}\Co_{50\AA}](X;\=\;8,\;10,\;14,\;18,\;22,\;26,\;28,\;38,\;48,\;58\;\AA,\;N\;=\;2,\;3,\;4,\;10,\;20)$ multilayers prepared by dc magnetron sputtering on the interlayer thickness of Cu (X), the number of multylayer(N) and annealing temperature has been performed. Resistance measurement were made by four terminal method, and the magnetic field applied to perpendicular and parallel for the current. The maximum magnetoresistance(MR) ratio(%) was appeared in the vicinity of $10\;\AA$ in Cu layer, and it was oscillated with the thickness of Cu. The MR ratio was increased with the number of layers N, however the ratio for the N = 4 layers decreased rather than the N = 3 layers. The dependence of the ratio on the annealing temperature was increased to $250^{\circ}C$.

  • PDF

Electrical and Magnetic Properties of Tunneling Device with FePt Magnetic Quantum Dots (FePt 자기 양자점 터널링 소자의 전기적 특성과 자기적 특성 연구)

  • Pak, Sang-Woo;Suh, Joo-Young;Lee, Dong-Uk;Kim, Eun-Kyu
    • Journal of the Korean Vacuum Society
    • /
    • v.20 no.1
    • /
    • pp.57-62
    • /
    • 2011
  • We have studied the electrical and magnetic transport properties of tunneling device with FePt magnetic quantum dots. The FePt nanoparticles with a diameter of 8~15 nm were embedded in a $SiO_2$ layer through thermal annealing process at temperature of $800^{\circ}C$ in $N_2$ gas ambient. The electrical properties of the tunneling device were characterized by current-voltage (I-V) measurements under the perpendicular magnetic fields at various temperatures. The nonlinear I-V curves appeared at 20 K, and then it was explained as a conductance blockade by the electron hopping model and tunneling effect through the quantum dots. It was measured also that the negative magneto-resistance ratio increased about 26.2% as increasing external magnetic field up to 9,000 G without regard for an applied electric voltage.

MR Characteristics of CoO based Magnetic tunnel Junction (CoO를 절연층으로 이용한 스핀 의존성 터널링 접합에서의 자기저항 특성)

  • 정창욱;조용진;안동환;정원철;조권구;주승기
    • Journal of the Korean Magnetics Society
    • /
    • v.10 no.4
    • /
    • pp.159-163
    • /
    • 2000
  • MR characteristics in magnetic tunnel junction using CoO as the oxide barrier were investigated. Spin-dependent tunnel junctions were fabricated on 4$\^$o/ tilt-cut (111)Si substrates in 3-gun magnetron sputtering system. The top and bottom ferromagnetic electrodes were Ni$\_$80/Fe$\_$20/(300 $\AA$) and Co(300 $\AA$), respectively. The oxide barriers (CoO) were formed by the thermal oxidation at room temperature in an O$_2$ atmosphere and the plasma oxidation. The increase of coercive field due to antiferromagnetic-ferromagnetic coupling has been observed in O$_2$plasma-oxidized CoO based junctions at room temperature. At a sensing current of 1 mA, MR ratios of O$_2$plasma-oxidized CoO based junction and thermal-oxidized CoO based junction at room temperature were 1% and 5%, respectively. Larger MR ratios are observed in magnetic tunnel juctions with thermal oxidized CoO when sensing current more than applied 1.5 mA. At a sensing current of 1.5 mA, we have observed MR value of 28 % and specific resistance (RA=R$\times$A) value of 10.9 ㏀$\times$$^2$. When specific resistance values reached 2.28 ㏀$\times$$^2$, we have observed that MR ratios become as high as 120%.

  • PDF

Soft Magnetoresistive Properties of Conetic Thin Film Depending on Ta Buffer Layer (버퍼층 Ta에 의존하는 코네틱 박막의 연자성 자기저항 특성)

  • Choi, Jong-Gu;Hwang, Do-Guwn;Lee, Sang-Suk;Choi, Jin-Hyub;Lee, Ky-Am;Rhee, Jang-Rho
    • Journal of the Korean Magnetics Society
    • /
    • v.19 no.6
    • /
    • pp.197-202
    • /
    • 2009
  • The property of soft magnetism for the Corning glass/non-buffer or buffer Ta/Conetic(NiFeCuMo)/Ta prepared by the ion beam deposition sputtering was studied. The effect of crystal property and post annealing treatment depending on the thickness of Conetic thin films was investigated. The coercivities of Conetic thin films with easy and hard direction along to the applying magnetic field during deposition were compared with each other. The coercivity and magnetic susceptibility of Ta(5 nm)/Conetic(50 nm) thin film were 0.12 Oe and 1.2 ${\times}\;10^4$, respectively. From these results, firstly, the Conetic thin film was more soft magnetism thin film than other one such as permalloy NiFe. Secondly, the usage of soft magnetism Conetic thin film for GMR-SV (giant magneoresistance-spin valve) or MTJ (Megnetic Tunnel Junction) structure in a low magnetic field can be possible.

ThE Variation of Magnetoresistande Ratio and Magnetization Curve by Insertion Co Layer in the$[Ni_{80}Fe_{20}/Cu/Co/Cu]$ Multilayers (교환 결합 상태가 다른 $[Ni_{80}Fe_{20}/Cu/Co/Cu]$ 다층 박막에서 Co 계면 삽입이 자기적 특성에 미치는 영향)

  • 이정주;최상준;홍재화;권순주
    • Journal of the Korean Magnetics Society
    • /
    • v.8 no.2
    • /
    • pp.79-85
    • /
    • 1998
  • The $[Ni_{80}Fe_{20}/Cu/Co/Cu]$ multilayers were grown by evaporation technique, and according to magnetic exchange coupling relation, magnetoresistance ratio and magnetization curve were studied by Co inserting $Ni_{80}Fe_{20}/Cu$ interface. Insertion of Co layer to the antiferromagnetically coupled system, i. e $t_{Cu} = 25\;{\AA}$, decrese the MR ratio contrary to previous reports. However the insertion to the ferromagneticalyl coupled $(t_{Cu} = 27\;{\AA})$ and the noncoupled $(t_{Cu} = 47\;{\AA})$ systems increase the ratio to 3.5 % and 6 % respectively. The results imply that the insertion change the magnetic exchange coupling state as well as the spin dependent scattering of conduction electrons. Besides, insertion of Co layer between Cu and $Ni_{80}Fe_{20}$ layer enhaces thermal stability to the 300 $^{\circ}C$, which indicates that insertion of Co has a role of the effective diffusion barrier.

  • PDF

Effects of Ultrathin Co Insertion Layer on Magnetic Anisotropy and GMR Properties of NiFe/Cu/Co Spin Valve Thin Films (NiFe/Cu 계면에 삽입된 Co 층이 NiFe/Cu/Co 스핀밸브 박막의 거대자기저항 특성과 자기이방성에 미치는 영향)

  • 김형준;조권구;주승기
    • Journal of the Korean Magnetics Society
    • /
    • v.9 no.5
    • /
    • pp.251-255
    • /
    • 1999
  • NiFe(60 $\AA$)/Co(0$\AA$$\leq$x$\AA$$\leq$15$\AA$)/Cu(60$\AA$)/Co(30$\AA$) spin valve thin films were prepared on 4$^{\circ}$ tilt-cut Si(111) substrates with a 50 $\AA$ thick Cu underlayer without applying any external magnetic field during the deposition, and the effects of inserted ultrathin Co layer on magnetic anisotropy and GMR properties of the NiFe(60 $\AA$)/Cu(60$\AA$)/Co(30$\AA$) spin valves were investigated. As the ultrathin Co layer was inserted into the NiFe/Cu interface of the spin valves, GMR ratio was increased from about 1.5% to 3.5%, and the easy axis of NiFe(60 $\AA$) layer was rotated by 90$^{\circ}$. Accordingly, it was aligned along the same direction with the easy axis of Co(30 $\AA$)layer. Therefore, squared R-H curves was obtained in the spin valves, which is favorable properties for the digital GMR devices such as MRAM. In order to investigate the change of magnetic anisotropy of NiFe layer of the spin valves in more details,XRD measurement was performed using NiFe(500 $\AA$) and NiFe(500 $\AA$)/Co(10 $\AA$) thin films on the same templates. Strong (220) NiFe peak was observed in both films regardless of the inserted Co layer, so it was thought that the variation of magnetic anisotropy of NiFe layer is from the interface effect, the change of interface from NiFe/Cu to NiFe/Co, rather than the volume effect such as the change of magnetocrystalline effect.

  • PDF

Magnetic Properties of CrO2 Thin Films Deposited by Thermal Deposition (열분해법으로 형성된 산화크롬 박막의 자기적 특성)

  • Choi, Hyun-Ju;Lim, Dae-Soon;Lee, Jeon-Kook
    • Journal of the Korean Ceramic Society
    • /
    • v.41 no.9
    • /
    • pp.653-656
    • /
    • 2004
  • We report the magnetic properties, microstructures, and crystal orientations of the CrO$_2$ thin films on TiO$_2$ single crystals. CrO$_2$ thin films were deposited by thermal decompositions with CrO$_3$ source materials. The microstructure of (110) oriented CrO$_2$ thin films deposited on (110) TiO$_2$ single crystals were uniform. As the oxygen flow rates increased, the resistivity, coercive field, and remnant magnetization of the CrO$_2$ thin films on TiO$_2$ single crystals decreased.