• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.28-31
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• 2008

We studied the effect of easy magnetization axis orientation with respect to the strip direction by measuring the magnetoresistance(MR), the magneto-optic Kerr effect(MOKE), and real-time domain evolution. The five strips were patterned on a single chip with the easy axis orientation of each strip relative to the longitudinal direction by around $0^{\circ}$, $18^{\circ}$, $36^{\circ}$, $54^{\circ}$ and $72^{\circ}$, respectively. The overall shape of field dependent MR was mostly governed by the anisotropy magnetoresistnace. The relative change of the longitudinal MR was significantly increased with increasing angle between the easy axis and strip direction, whereas, the transverse MR variation rate was decreased with increasing angle. Several MR steps were observed during the magnetization reversal, and the simultaneous measurement of the MOKE and the domain images identified that the MR steps were associated with evolution of the oppositely directed magnetic domain.

• Journal of Magnetics
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• v.2 no.1
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• pp.22-24
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• 1997

FeN thin films were deposited by RF-reactive diode sputtering to investigate magnetic characteristics variation due to substrate tilt during the film deposition, and their magnetic properties were measured by VSM, SEM and AFM. When the substrate tilt pivot edges were parallel to the applied field, the magnetic anisotropy was increased When the substrate tilt pivot edges were perpendicular to the applied field, the easy magnetization axis became the hard magnetization axis, and the hard axis became the easy axis as the tilt angles were increased. The reason is believed to be due to the fact that the tilt induced shape magnetic anisotropy became larger than the field induced magnetic anisotropy by DC magnetic field as the crystal grains are enlongated along the substrate tilt pivot edges due to "oblique incidence anisotropy" commonly found in eveporated thin films.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1475-1477
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• 2001

In odor to set high saturation magnetization and coercivity, it had need to orient axis of easy magnetization of CoCr-based thin film perpendicular direction(c-axis) to the substrate plane. It was known that crystalline orientation of CoCr-based thin film was improved by introducing underlayer like Ti, Ge. We prepared singlelayer and double layer with Si underlayer by Facing Targets Sputtering System. As a result, intensity and c-axis dispersion angle ${\Delta}{\theta}_{50}$ of singlelayer were improved with increasing film thickness. Also, it was found that CoCr/Si and CoCrTa/Si double layer showed good c-axis dispersion angle due to introducing Si.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.287-296
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• 2000

We have developed a three-axis configurational in situ SMOKE apparatus by which three-dimensional vector magnetization reversal processes are studied for ultrathin Co films grown on a Pd (111) single crystal in the thickness range of spin-reorientation transition. This study provides a better understanding of magnetization reversal motions with the knowledge of 3 components of magnetization vector at the transition of an easy axis of magnetization from the film normal at 5 ML Co to in-plane at 6 ML Co (ML notes monolayer). For a 5.25 ML Co, it was observed that a slightly canted magnetization vector from the film normal rotated in the film plane under an applied field direction parallel to the film normal.

• Journal of Magnetics
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• v.6 no.2
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• pp.53-56
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• 2001

We have developed a three-axis configurational in situ SMOKE apparatus by which three-dimensional vector magnetization reversal processes are studied for ultrathin Co films grown on a Pd (111) single crystal in the thickness range of spin reorientation transition. This study provides a better understanding of magnetization reversal motions with the knowledge of three components of the magnetization vector at the transition of an easy axis of magnetization from the film normal at 5 ML Co to in-plane at 6 ML Co (ML denotes monolayer). For a 5.25 ML Co, it was observed that a slightly canted magnetization vector from the film normal rotated in the film plane under an applied field direction parallel to the film normal.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.212.1-212.1
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• 2007

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.29-29
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• 2009

• Journal of the Korean Magnetics Society
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• v.23 no.3
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• pp.98-103
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• 2013

The magnetic easy axis of the ferromagnetic layer for the dual-type GMR-SV (giant magnetoresistance-spin valve) having NiFe/Cu/NiFe/IrMn/NiFe/Cu/NiFe multuilayer structure controlled by the post annealing treatment. The magnetoresistive curves of a dual-type IrMn based GMR-SV depending on the direction of the magnetic easy axis of the free and the pinned layers are measured by the different angles for the applied fields. By investigating the switching process of magnetization for an arbitrary measuring direction, the optimum annealing temperature having a steady and isotropy magnetic sensitivity of 2.0 %/Oe was $105^{\circ}C$. This result suggests that the in-plane orthogonal magnetization for the dual-type GMR-SV film can be used by a high sensitive biosensor.

• Journal of the Korean Magnetics Society
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• v.17 no.5
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• pp.188-193
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• 2007

We simulated the magnetization reversal behavior of submicron-thickness magnetic films by applying pulses of sub-ns-long durations and amplitudes along the easy axis. The films were rectangular and elliptical $Ni_{80}Fe_{20}$, and their thickness was 2 nm and 4 nm. We observed different behaviors depending upon the shape and thickness of the films and found a normal non-switching in regions in which we expected complete switching after relaxation. In the elliptical film, the non-switching regions were found to be random and to be widely distributed throughout the switching map. The strong demagnetization field along the z-axis, the film thickness direction, is likely responsible for this abnormal behavior. In the rectangular film, the abnormal non-switching regions were less distributed than they were in the elliptical film due to edge domains resulting from the small $M_z$ or demagnetization field during the switching. Our simulation confirms that large demagnetization is detrimental to the ultra-fast magnetization reversal of magnetic ultra-thin films.

• Journal of Magnetics
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• v.21 no.1
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• pp.6-11
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• 2016

The magnetic anisotropy energy (MAE) and the saturation magnetization $B_s$ of (110) $Fe_nCo_n$ heterostructures with n = 1, 2, and 3 are investigated in first-principles within the density functional theory by using the precise full-potential linearized augmented plane wave (FLAPW) method. We compare the results employing two different exchange correlation potentials, that is, the local density approximation (LDA) and the generalized gradient approximation (GGA), and include the spin-orbit coupling interaction of the valence states in the second variational way. The MAE is found to be enhanced significantly compared to those of bulk Fe and Co and the magnetic easy axis is in-plane in agreement with experiment. Also the MAE exhibits the in-plane angle dependence with a two-fold anisotropy showing that the $[1{\overline{I}}0]$ direction is the most favored spin direction. We found that as the periodicity increases, (i) the saturation magnetization $B_s$ decreases due to the reduced magnetic moment of Fe far from the interface, (ii) the strength of in-plane preference of spin direction increases yielding enhancement of MAE, and (iii) the volume anisotropy coefficient decreases because the volume increase outdo the MAE enhancement.