论文标题
Mntio $ _3 $中磁弹性耦合和磁各向异性的作用
The role of magnetoelastic coupling and magnetic anisotropy in MnTiO$_3$
论文作者
论文摘要
我们报告了通过热膨胀，磁截图，磁化和特定的热量测量以及\ MTO \的低能量磁激励研究所研究的热力学特性，并研究了磁弹性耦合和磁动反应如何影响远距离顺序和磁相图的演化。具体而言，我们通过高频电子自旋共振（HF-ESR）光谱法利用高分辨率电容扩张法和抗铁磁共振（AFMR）研究。各向异性的作用是通过$ b _ {\ rm {sf}} $〜$ \ simeq 6 $ 〜t和$ \ partial t _ {\ rm n}/\ partial b $中的相应符号变化反映的自旋晶体降低反映的。对AFMR模式的分析使我们能够建立零场激发差距$δ$及其温度依赖性。我们得出有效的各向异性场$ b_ \ mathrm {a} = 0.16（1）$ 〜t，主要源自平面外最近的邻次偶极 - 偶极 - 偶极 - 偶极相互作用。尽管几乎完全淬火了轨道时刻，但我们的数据显示出明显的热膨胀和磁截图异常，分别为$ t _ {\ rm n} $和$ b _ {\ rm {sf {sf}} $，允许实验性地确定相当可观的单十级压力依赖性，即p _ {\ rm c} = -0.20（2）$ 〜t/gpa，$ \ partial t _ {\ rm n}/\ partial p_b = 0.69（12）$ 〜k/gpa，$ 〜k/gpa和$ \ partial t _ {\ rm n}/\ rm n}/\ partial p p _ p _ c = -2.0（4）值得注意的是，如各向异性晶格失真所示，短距离磁顺序至少出现至少3 $ t _ {\ rm n} $，违反了恒定的grüneisen行为以及HF-ESR检测到的局部磁场。
We report the thermodynamic properties studied by thermal expansion, magnetostriction, magnetisation, and specific heat measurements as well as the low-energy magnetic excitations of \mto\ and investigate how magneto-elastic coupling and magnetic anisotropy affect the evolution of long-range order and the magnetic phase diagram. Specifically, we utilise high-resolution capacitance dilatometry and antiferromagnetic resonance (AFMR) studies by means of high-frequency electron spin resonance (HF-ESR) spectroscopy. The role of anisotropy is reflected by spin-reorientation at $B_{\rm{SF}}$~$\simeq 6$~T and a corresponding sign change in $\partial T_{\rm N}/\partial B$. Analysis of the AFMR modes enables us to establish the zero-field excitation gap $Δ$ as well as its temperature dependence. We derive the effective anisotropy field $B_\mathrm{A} = 0.16(1)$~T which predominately originates from out-of-plane nearest-neighbour dipole-dipole interactions. Despite the nearly fully quenched orbital moment, our data show pronounced thermal expansion and magnetostriction anomalies at $T_{\rm N}$ and $B_{\rm{SF}}$ , respectively, which allows the experimental determination of sizable uniaxial pressure dependencies, i.e., $\partial B_{\rm SF}/\partial p_{\rm c} = -0.20(2)$~T/GPa, $\partial T_{\rm N}/ \partial p_b = 0.69(12)$~K/GPa, and $\partial T_{\rm N}/ \partial p_c = -2.0(4)$~K/GPa. Notably, short-range magnetic order appears up to at least 3$T_{\rm N}$ , as indicated by anisotropic lattice distortion, the violation of a constant Grüneisen behavior, and the presence of local magnetic fields detected by HF-ESR.
