TY - CHAP
T1 - Spin polarization in Heusler alloy films
AU - Takahashi, Yukiko K.
AU - Hono, Kazuhiro
N1 - Publisher Copyright:
© Springer International Publishing Switzerland 2016.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Spin polarization measurements are essential for searching new alloys with high spin polarization. While tunneling magnetoresistance (TMR) measurements have been used to estimate the spin polarization of ferromagnetic (FM) electrodes of magnetic tunneling junctions (MTJs), it requires thin film stack and tedious microfabrication processes to prepare TMR pillars. On the other hand, point contact Andreev reflection (PCAR) can estimate current spin polarizations of bulk alloys relatively easily. Low temperature spin polarization of a series of quaternary substitutional alloys, Co2Y(Z1 − xZ´x), designed based on the Fermi level tuning, have been investigated using PCAR. Promising alloys were screened and they were evaluated as ferromagnetic (FM) layers of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) pseudo spin valves. Some quaternary Heusler alloys, such as Co2Fe(Al0.5Si0.5), Co2Mn(Ge0.75Ga0.25) and Co2Fe(Ge0.5Ga0.5) were found to be excellentFMlayer forCPP-GMR. Recent theoretical and experimental investigations on the correlation between anisotropy magnetoresistance (AMR) and MR outputs suggest that AMR measurements will be more effective way for screening alloys for high spin polarization, as it can estimate spin polarization at finite temperatures.
AB - Spin polarization measurements are essential for searching new alloys with high spin polarization. While tunneling magnetoresistance (TMR) measurements have been used to estimate the spin polarization of ferromagnetic (FM) electrodes of magnetic tunneling junctions (MTJs), it requires thin film stack and tedious microfabrication processes to prepare TMR pillars. On the other hand, point contact Andreev reflection (PCAR) can estimate current spin polarizations of bulk alloys relatively easily. Low temperature spin polarization of a series of quaternary substitutional alloys, Co2Y(Z1 − xZ´x), designed based on the Fermi level tuning, have been investigated using PCAR. Promising alloys were screened and they were evaluated as ferromagnetic (FM) layers of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) pseudo spin valves. Some quaternary Heusler alloys, such as Co2Fe(Al0.5Si0.5), Co2Mn(Ge0.75Ga0.25) and Co2Fe(Ge0.5Ga0.5) were found to be excellentFMlayer forCPP-GMR. Recent theoretical and experimental investigations on the correlation between anisotropy magnetoresistance (AMR) and MR outputs suggest that AMR measurements will be more effective way for screening alloys for high spin polarization, as it can estimate spin polarization at finite temperatures.
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U2 - 10.1007/978-3-319-21449-8_12
DO - 10.1007/978-3-319-21449-8_12
M3 - Chapter
AN - SCOPUS:84946944968
T3 - Springer Series in Materials Science
SP - 295
EP - 318
BT - Springer Series in Materials Science
PB - Springer Verlag
ER -