Study on non-strain single crystal MR junctions using half metallic ferromagnetic thin films.

使用半金属铁磁薄膜的非应变单晶MR结的研究。

基本信息

批准号：
16360313
负责人：
MATSUI Masaaki
金额：
$ 9.15万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360313/
关键词：
half metal thin film perovskite oxide film Heuslar alloy film Tunneling magneto-resistance Giant magneto-resistance single crystal film Preferred oriented film band structure ハーフメタル強磁性体単結晶薄膜ペロブスカイト酸化物ホイスラー合金スピン分極率アンドロエフ反射

项目摘要

The methods to fabricate the high quality and single crystal half metallic perovskite ferromagnetic (La_<0.7>Sr_<0.3>MnO_3 (LSMO), Sr_2FeMnO_6 (SFMO), Sr_2CrReO_6(SCRO)) films were established, where the magnetron sputtering method was employed. The conditions to make the non-strain single crystal TMR junctions using the high quality perovskite oxides are followings. 1) The misfit between substrate and film should be minimized. 2) In order to minimize the mismatching, furthermore, it is better that an intermediate layer such as Ba_<0.4>Sr_<0.6>TiO_3 is grown between substrate and film. 3) The oxygen partial pressure is important in cooling process after growth of the film. Too small partial pressure deletes the oxygen atoms in film and too much pressure make the non ferromagnetic oxides layer. The pressure should be optimized. 4) In the case of argon gas milling in the process of fabrication of MR devices, the film was damaged by the strain and the deletion of oxygen atoms from film su … More rface layer (about 40nm). Sometimes, the electrical resistance was extremely increased at low temperatures due to the damage. The damage was recovered by the annealing above 900℃ in the oxygen atmosphere. It is important to anneal in the fabrication process of MR devices. We optimized the above conditions. Then, the TMR ratios of 64% for LSMO/SrTiO_3/LSMO, 14% for SFMO/ SrTiO_3/Co and 114% for SrCrReO/MgO/Co junctions were observed. The spin polarization of the ferromagnetic half metals was measured by the Andreev reflection method using NbN superconductor layer, inserting an insulator layer between NbN and the half metal. The methods to fabricate the high quality single crystal films or the preferred oriented films of Heusler alloys such as Co_2MnGe, Co_2MnGa, and Co_2MnSi were established. TMR junctions composed by (100) or (110) preferred oriented Co_2MnGe film was fabricated on a Si substrate. The origin of half metallic property of Co-based Heusler alloys or non half metallic property of Ni-based Heusler alloys was discussed by the band calculations and experiments. Less

制造高质量和单晶半金属钙钛矿铁磁（la_ <0.7> sr_ <0.3> mno_3（lsmo），sr_2femno_6（sfmo），sr_2crreo_6（scro_6（scro））的方法已建立了镁质剂的方法。以下是使用高质量的钙钛矿氧化物来制作非应变单晶TMR连接的条件。 1）应该最大程度地减少底物和胶片之间的误差。 2）为了最大程度地减少不匹配的，更好的是，诸如BA_ <0.4> SR_ <0.6> TIO_3之类的中间层在底物和膜之间生长。 3）氧气部分压在膜生长后的冷却过程中很重要。太小的部分压删除了薄膜中的氧原子，而太多的压力使非铁磁氧化物层层。压力应优化。 4）对于在MR设备制造过程中氩气铣削的情况下，膜受到菌株的损坏，并从膜SU中删除了氧原子……更多的rface层（约40nm）。有时，由于损坏，在低温下，电阻极高。通过在氧气气氛中的900℃以上的退火来恢复了损害。在MR设备的制造过程中退火很重要。我们优化了上述条件。然后，观察到LSMO/SRTIO_3/LSMO的TMR比为64％，SFMO/SRTIO_3/CO的TMR比为14％，SRCRREO/MGO/CO连接的TMR比为14％，为114％的TMR比率为114％。通过使用NBN超导体层的Andreev反射方法测量铁磁半金属的自旋极化，并在NBN和半金属之间插入绝缘体层。建立了制造高质量的单晶膜的方法或Heusler合金（例如CO_2MNGE，CO_2MNGA和CO_2MNSI）的首选膜。由（100）或（110）首选的CO_2MNGE膜组成的TMR连接在SI基板上制造。频段计算和实验讨论了基于CO的Heusler合金或基于Ni的Heusler合金的一半金属特性的起源。较少的