Aperiodical oscillation of interlayer coupling in epitaxial Co/Ir(001) superlattices
Aperiodical oscillation of interlayer coupling in epitaxial Co/Ir(001) superlattices
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外延Co/Ir(001)超晶格层间耦合的非周期振荡
DOI：
10.1103/physrevb.60.12957
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发表时间：
1999
影响因子：
3.7
通讯作者：
M. Salamon
中科院分区：
文献类型：
--
作者：
H. Yanagihara;E. Kita;M. Salamon
通过分子束外延在 MgO(001) 衬底上成功生长了高质量外延钴铱超晶格，并发现其表现出具有强耦合常数的反常振荡层间交换耦合。非周期反铁磁 (AF) 峰出现在 Ir 层厚度为 5 \AA{}、15 \AA{} 和 33 \AA{} 处。获得的最大磁阻 (MR) 比率为 $\ensuremath{\approx}1.1%$，并且第一和第二 AF 峰值几乎相同。对应于第一个 AF 峰值的层间耦合非常强，即使在高达 90 kOe 的外加磁场中，磁化强度也不会饱和。室温下MR曲线估计的层间交换常数值接近第一个AF峰值超过2.2 ${\mathrm{e}\mathrm{r}\mathrm{g}/\mathrm{c}\mathrm{m}}^{2}$。观察到[100]和[110]方向之间的面内磁化过程的区别，并且发现易磁化轴沿着面内的[110]轴。非周期性振荡被认为表明层间交换常数的多周期性。
High quality epitaxial cobalt-iridium superlattices were successfully grown on MgO(001) substrates via molecular-beam epitaxy and were found to exhibit anomalous oscillatory interlayer exchange coupling with a strong coupling constant. The aperiodical antiferromagnetic (AF) peaks appear at Ir layer thicknesses of 5 \AA{}, 15 \AA{}, and 33 \AA{}. Maximum magnetoresistance (MR) ratios of $\ensuremath{\approx}1.1%$ are obtained and are almost the same for the first and the second AF peaks. The interlayer coupling corresponding to the first AF peak is so strong that the magnetization did not saturate even in an applied field up to 90 kOe. The estimated value of the interlayer exchange constant by MR curves at room temperature is more than 2.2 ${\mathrm{e}\mathrm{r}\mathrm{g}/\mathrm{c}\mathrm{m}}^{2}$ close to the first AF peak. A distinction of the in-plane magnetization process between [100] and [110] directions is observed and the easy axis of magnetization is found to be along the [110] axis in plane. The aperiodic oscillations are thought to indicate multiperiodicity of the interlayer exchange constants.