Investigation of temperature dependence of magnetic properties of Cr$_2$O$_3$ thin film structure using a magnetic field imaging technique based on Nitrogen-Vacancy centres in diamond crystal
Andris Berzins, Janis Smits, Andrejs Petruhins, Roberts Rimsa, Martins Zubkins, Gatis Mozolevskis
备注：
The measurements and simulations presented in this manuscript are correct, however, the data interpretation (magnetic field as a main source of the signal) is incorrect. After submission to a scientific journal and discussion with referees, we understood that the main cause of the ODMR frequency shifts is strain-related. Thus the authors decided to present it as a new manuscript: arXiv:2111.12979
提出了一种基于金刚石晶体色心的磁场成像方法，并将其应用于薄膜结构。为了证明我们的设备的能力，我们已经使用它的微观尺度上的Cr $_2$ O $_3$薄膜结构以上和以下内尔温度的磁性能的表征。所获得的测量结果清楚地识别出在19 $^{\circ}$ C（低于Cr $_2$ O $_3$的Néel温度）下具有意想不到的抗磁性类似行为的Cr $_2$ O $_3$薄膜的磁性相变的检测。为了更好地了解薄膜产生的磁场，我们模拟了薄膜表面附近的磁场。我们还分析了光学检测的磁共振（ODMR）的配置文件，以确保测量的属性只与光学检测的磁共振的移位。我们展示了如何氮空位中心为基础的磁强计可以提供一个方便的平台，相变动力学和空间磁场分布的薄膜的研究，可以媲美其他广泛使用的测量技术。
英文摘要：
This work presents a magnetic field imaging method based on color centres in diamond crystal applied to thin film structure. To demonstrate the capacity of our device we have used it for characterization of magnetic properties in microscopic scale of Cr$_2$O$_3$ thin film structure above and below Néel temperature. The obtained measurement results clearly identify the detection of the magnetic phase transition of Cr$_2$O$_3$ thin film with an unexpected diamagnetic like behaviour at 19$^{\circ}$C (below the Néel temperature of Cr$_2$O$_3$). To have better insights in the magnetic fields created by the thin films we present simulations of the magnetic fields near the thin film surface. We also analysed the optically detected magnetic resonance (ODMR) profiles to be sure that the measured property is related only to the shift of the optically detected magnetic resonance. We demonstrate how Nitrogen-Vacancy centre based magnetometry can deliver a convenient platform for research of phase transition dynamics and spatial magnetic field distributions of thin films, that can rival other widely used measurement techniques.
