TY - JOUR
T1 - Hybrid Memory Layer with Low Curie Temperature COPD/Pd Multilayer for High-Density Magnetic Random-Access Memory Cells
AU - Zhao, W.
AU - Dong, X.
AU - Kimura, T.
AU - Kato, T.
AU - Oshima, D.
AU - Sonobe, Y.
AU - Kawato, Y.
AU - Iwata, S.
N1 - Funding Information:
ACKNOWLEDGMENT The authors would like to thank M. Kumazawa of Nagoya University, Nagoya, Japan, for his assistance with the experiments. This work was support by JSPS KAKENHI Grant 16H04328, Grant 16K18091, Grant 17H03249, and Grant 17K18878. A part of this work was conducted at the Nagoya University, Nanofabrication Platform, supported by “Nanotechnology Platform Program” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
© 1965-2012 IEEE.
PY - 2018/11
Y1 - 2018/11
N2 - We investigated switching behavior of the hybrid structures consisting of low Curie temperature (TC) and high TC layers. The TC of [Co (0.3 nm)/Pd (1.2 nm)]6 and [Co54Pd46 (0.3 nm)/Pd (1.2 nm)]6 multilayers (MLs) were confirmed to have much higher than 200 °C and around 110 °C, respectively. In the bi-ML hybrid structure with Co/Pd and CoPd/Pd MLs, the two MLs are exchange-coupled at room temperature, and the CoPd/Pd ML was switched following the magnetization of the high TC Co/Pd ML at high temperature (170 °C) at which the CoPd/Pd ML becomes paramagnetic. The tri-layered hybrid structure with a stack of [Co (0.4 nm)/Pt (1.2 nm)]6/[Co48Pd52 (0.3 nm)/Pd (1.2 nm)]3/[Co (0.4 nm)/Pd (1.2 nm)]3 was also investigated. The tri-ML stack showed one-step hysteresis loop at room temperature and two-step loop at higher than 120 °C due to the loss of magnetic order of the intermediate low TC CoPd/Pd ML. From the data of tri-ML stack, the exchange coupled and decoupled situations between Co/Pt and Co/Pd MLs were found to be realized by changing the temperature from room temperature to around 150 °C.
AB - We investigated switching behavior of the hybrid structures consisting of low Curie temperature (TC) and high TC layers. The TC of [Co (0.3 nm)/Pd (1.2 nm)]6 and [Co54Pd46 (0.3 nm)/Pd (1.2 nm)]6 multilayers (MLs) were confirmed to have much higher than 200 °C and around 110 °C, respectively. In the bi-ML hybrid structure with Co/Pd and CoPd/Pd MLs, the two MLs are exchange-coupled at room temperature, and the CoPd/Pd ML was switched following the magnetization of the high TC Co/Pd ML at high temperature (170 °C) at which the CoPd/Pd ML becomes paramagnetic. The tri-layered hybrid structure with a stack of [Co (0.4 nm)/Pt (1.2 nm)]6/[Co48Pd52 (0.3 nm)/Pd (1.2 nm)]3/[Co (0.4 nm)/Pd (1.2 nm)]3 was also investigated. The tri-ML stack showed one-step hysteresis loop at room temperature and two-step loop at higher than 120 °C due to the loss of magnetic order of the intermediate low TC CoPd/Pd ML. From the data of tri-ML stack, the exchange coupled and decoupled situations between Co/Pt and Co/Pd MLs were found to be realized by changing the temperature from room temperature to around 150 °C.
KW - Co-based multilayer (ML)
KW - Curie temperature (Tc)
KW - exchange coupling
KW - magnetic random access memory (MRAM)
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U2 - 10.1109/TMAG.2018.2828138
DO - 10.1109/TMAG.2018.2828138
M3 - Article
AN - SCOPUS:85047016984
SN - 0018-9464
VL - 54
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 11
M1 - 8359443
ER -