Soon Young Jeong

Current Density and Thickness Effects on Magnetic Properties of Electrodeposited CoPt Magnetic Films

The dominant magnetization reversal behavior of electrodeposited CoPt samples with various thicknesses deposited at different current densities was the domain wall motion by means of wall pinning. The magnetic interaction mechanism was dipolar interaction for all samples. The dipolar interaction strength was significantly affected by the sample thickness rather than by the current density, while the magnetic properties were closely related to the current density.

Growth Kinetics of Fe Films Electrodeposited on n-Si(111)

Iron thin films were grown directly on n-Si(111) substrates by pulsed electrodeposition in a non-aqueous 0.1 M FeCl2 electrolyte solution. In this solution, Fe2+/Si interface showed a good diode behavior by forming a Schottky barrier. From single-step potential experiment in the potential ranges from 1.0 to 1.4 V, the formation of Fe nuclei in the early deposition stages was proceeded according to the three dimensional (3D) instantaneous nucleation followed by diffusion-limited growth rather than a progressive one. When depositing Fe using pulse potentials with the maximum voltage of 1.0 and 1.5 V, it was found that nucleation mechanism of Fe is similar with the results for the case of single-step potential experiment. However, nucleation during depositing Fe at 2.0 V initiated according to the progressive mechanism. Fe thin films, which obtains from pulse potential of 1.4 V with a frequency of 300 Hz, revealed a highly oriented columnar structures perpendicular to the surface of Si(111) and that only the single phase α-Fe(110) was grown on Si(111) substrate.

Magnetization Reversal Mechanism and Magnetic Properties of Co/Pd Multilayers

To study the magnetization reversal mechanism and the magnetic properties of Co/Pd multilayers fabricated at various Ar sputtering pressures, we first demagnetized the samples using the field-demagnetization method, then measured initial and magnetization curves and minor loops. The coercivity and the perpendicular magnetic anisotropy were obtained from the parallel and perpendicular magnetization curves measured at different temperatures. We interpret our experimental results by applying several qualitative methods. From this study, we found that the domain wall pinning with a small pinning site is the dominant magnetization reversal mechanism.

Sputtering pressure effects on magnetization reversal mechanism and magnetic switching volumes of CoSm/Cr films

The sputtering pressure effects on magnetization reversal and magnetic switching volumes of CoSm/Cr films have been investigated. It is found that the magnetization reversal changed from wall pinning for samples prepared at low pressure to single particle rotation for samples prepared at high pressure. The magnetic switching volumes increased with increasing the Ar pressure to values in the range of 5.2-9.0 ×10-18 cm3. These switching volumes satisfy Sharrocks requirement for the thermal stability of high-density magnetic recording.

Magnetic Interaction and Magnetization Reversal Phenomenon of Cr/CoSm/Cr Magnetic Films Deposited with Different Sputtering Pressures of Underlayer

The CoSm magnetic layer with a thickness of 30 nm was grown at a pressure of 20 mTorr on the Cr underlayer prepared with different Ar sputtering pressures. The effect of underlayer deposition conditions on magnetic interaction mechanism and magnetization reversal phenomenon was investigated. The Henkel plot, IFF and ΔM obtained from measurement curves showed that the dipole interaction was dominant in all samples, but the strength of the dipole interaction decreased with increasing sputtering pressure. In addition, all samples were found to be the dominant reversal phenomenon of the domain wall motion controlled by the domain wall pinning.

Magnetic Interaction Effect on Activation Volume and Area of CoPt Magnetic Films

The magnetic interaction effect on the magnetic activation volume and area of electrodeposited CoPt magnetic films was investigated. The dipolar interaction was predominant interaction mechanism for all samples. And the interaction strength was increased with decreasing current density and increased with increasing sample thickness. Although the activation volumes of the samples fabricated at low current density were larger than those of the high current density samples, the sample thickness seemed to have little influence on the variation of activation volume. But it was found that the activation area was apparently affected by the magnetic interaction strength as well as the current density.

Magnetic Interaction and Switching Volumes in CoSm/Cr Magnetic Films

The sputtering pressure dependence of magnetic switching volume and the nature of magnetic intergranular interaction in CoSm/Cr films have been investigated using several magnetic characterization techniques. As the results, we found that magnetic switching volume strongly correlates to the nature and strength of magnetic intergranular interaction determined on the basis of dc demagnetization remanence and isothermal remanence curves. Also the sign of interaction field factor is closely related to the nature of magnetic intergranular interaction.