论文标题
铁磁性绝缘体GDTIO $ _3 $中的磁弹性耦合到连贯的声音声子模式
Magneto-Elastic Coupling to Coherent Acoustic Phonon Modes in Ferrimagnetic Insulator GdTiO$_3$
论文作者
论文摘要
在这项工作中，我们使用超快的光泵探针反射率和磁光光谱法调查了一种有前途的浮雕工程和磁控制的有前途的候选材料$ _ {3} $。 gdtio $ {} _ {3} $是一个具有铁磁性和轨道订购的基态（\ textit {t $ {} _ {c} $} = 32 K）的莫特 - 哈伯德绝缘子。我们观察到响应于上述带 - 660 nm激发的光诱导的反射率信号中磁相变的多个特征。通过KERR光谱测量的磁化动力学揭示了旋转晶格耦合时标的铁磁顺序的光扰动，突出了GD $ {}^{3+} $和Ti $ {}^{}^{3+}^{3+} $磁性副标的竞争。此外，反射和KERR动力学中存在强相干振荡，这归因于泵脉冲发射的声学应变波。这种声学模式的幅度高度取决于系统的磁顺序，在\ textit {t $ {} _ {c} $}时，大小急剧生长，表明强磁弹性耦合。涉及应变诱导的磁交换相互作用的修饰的驾驶机制意味着一种间接的方法，将光耦合到磁性自由度，并强调GDTio $ {} _ {3} $作为可调量子量的潜力。
In this work we investigate single crystal GdTiO$_{3}$, a promising candidate material for Floquet engineering and magnetic control, using ultrafast optical pump-probe reflectivity and magneto-optical Kerr spectroscopy. GdTiO${}_{3}$ is a Mott-Hubbard insulator with a ferrimagnetic and orbitally ordered ground state (\textit{T${}_{C}$} = 32 K). We observe multiple signatures of the magnetic phase transition in the photoinduced reflectivity signal, in response to above band-gap 660 nm excitation. Magnetic dynamics measured via Kerr spectroscopy reveal optical perturbation of the ferrimagnetic order on spin-lattice coupling timescales, highlighting the competition between the Gd${}^{3+}$ and Ti${}^{3+}$ magnetic sub-lattices. Furthermore, a strong coherent oscillation is present in the reflection and Kerr dynamics, attributable to an acoustic strain wave launched by the pump pulse. The amplitude of this acoustic mode is highly dependent on the magnetic order of the system, growing sharply in magnitude at \textit{T${}_{C}$}, indicative of strong magneto-elastic coupling. The driving mechanism, involving strain-induced modification of the magnetic exchange interaction, implies an indirect method of coupling light to the magnetic degrees of freedom and emphasizes the potential of GdTiO${}_{3}$ as a tunable quantum material.
