• Title/Summary/Keyword: Amorphous materials

Search Result 1,762, Processing Time 0.028 seconds

Spatial Distributions of Alloying Elements Obtained from Atom Probe Tomography of the Amorphous Ribbon Fe75C11Si2B8Cr4

  • Shin, Jinkyung;Yi, Seonghoon;Pradeep, Konda Gokuldoss;Choi, Pyuck-Pa;Raabe, Dierk
    • Korean Journal of Materials Research
    • /
    • v.23 no.3
    • /
    • pp.190-193
    • /
    • 2013

  • Spatial distributions of alloying elements of an Fe-based amorphous ribbon with a nominal composition of $Fe_{75}C_{11}Si_2B_8Cr_4$ were analyzed through the atom probe tomography method. The amorphous ribbon was prepared through the melt spinning method. The macroscopic amorphous natures were confirmed using an X-ray diffractometer (XRD) and a differential scanning calorimeter (DSC). Atom Probe (Cameca LEAP 3000X HR) analyses were carried out in pulsed voltage mode at a specimen base temperature of about 60 K, a pulse to base voltage ratio of 15 %, and a pulse frequency of 200 kHz. The target detection rate was set to 5 ions per 1000 pulses. Based on a statistical analyses of the data obtained from the volume of $59{\times}59{\times}33nm^3$, homogeneous distributions of alloying elements in nano-scales were concluded. Even with high carbon and strong carbide forming element contents, nano-scale segregation zones of alloying elements were not detected within the Fe-based amorphous ribbon. However, the existence of small sub-nanometer scale clusters due to short range ordering cannot be completely excluded.

  • https://doi.org/10.3740/MRSK.2013.23.3.190 인용 PDF KSCI

Magnetic and Structural Properties of CoFeZr Alloy Films and Magnetoresistive Properties of Spin Valves Incorporating Amorphous CoFeZr Layer (CoFeZr 합금박막의 미세구조, 자기적 특성 및 비정질 CoFeZr 합금박막을 사용한 스핀밸브의 자기저항 특성에 관한 연구)

  • Ahn, Whang-Gi;Park, Dae-Won;Kim, Ki-Su;Lee, Seong-Rae
    • Journal of the Korean Magnetics Society
    • /
    • v.18 no.6
    • /
    • pp.227-231
    • /
    • 2008

  • Magnetic and structural properties of CoFeZr alloy films as a function of Zr concentration and magnetoresistive properties of spin valves incorporated with amorphous CoFeZr alloy films have been studied. Magnetization and coercivity of CoFeZr alloy films decreased as the Zr content increased. A single amorphous CoFeZr phase was formed when the Zr content is about above 18 at%. Magnetoresistance ratio and exchange coupling field of spin valves with amorphous CoFeZr were reduced slightly as compared with spin valves with CoFe because the resistance of amophous CoFeZr is higher than that of crystalline CoFe. However, the ${\Delta}{\rho}$ of spin valves with amorphous CoFeZr was improved due to reduction of current shunting.

  • https://doi.org/10.4283/JKMS.2008.18.6.227 인용 PDF KSCI

Thermal Stability of Amorphous Ti-Cu-Ni-Sn Prepared by Mechanical Alloying

  • Oanha, N.T.H.;Choi, P.P.;Kim, J.S.;Kim, J.C.;Kwone, Y.S.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
    • /
    • 2006.09b
    • /
    • pp.953-954
    • /
    • 2006

  • Ti-Cu-Ni-Sn quaternary amorphous alloys of $Ti_{50}Cu_{32}Ni_{15}Sn_3$, $Ti_{50}Cu_{25}Ni_{20}Sn_5$, and $Ti_{50}Cu_{23}Ni_{20}Sn_7$ composition were prepared by mechanical alloying in a planetary high-energy ball-mill (AGO-2). The amorphization of all three alloys was found to set in after milling at 300rpm speed for 2h. A complete amorphization was observed for $Ti_{50}Cu_{32}Ni_{15}Sn_3$ and $Ti_{50}Cu_{25}Ni_{20}Sn_5$ after 30h and 20h of milling, respectively. Differential scanning calorimetry analyses revealed that the thermal stability increased in the order of $Ti_{50}Cu_{32}Ni_{15}Sn_3$, $Ti_{50}Cu_{25}Ni_{20}Sn_5$, and $Ti_{50}Cu_{23}Ni_{20}Sn_7$.

  • PDF