Critical competition between two distinct orbital-spin ordered states in perovskite vanadates
Critical competition between two distinct orbital-spin ordered states in perovskite vanadates
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DOI：
10.1103/physrevb.82.144425
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发表时间：
2010-10
影响因子：
3.7
通讯作者：
J. Fujioka;T. Yasue;S. Miyasaka;Y. Yamasaki;T. Arima;H. Sagayama;T. Inami;K. Ishii;Y. Tokura
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文献类型：
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作者：
J. Fujioka;T. Yasue;S. Miyasaka;Y. Yamasaki;T. Arima;H. Sagayama;T. Inami;K. Ishii;Y. Tokura
我们通过测量磁化强度、介电常数、比热、拉曼散射光谱和X射线衍射研究了钙钛矿钒酸盐（Y，Dy和Ho）的自旋/轨道相图，着重于自旋和离子动量之间的相互作用。在无磁矩的情况下，观察到C型自旋/G型轨道有序态和G型自旋/C型轨道有序态之间的热诱导相变。通过与中的自旋/轨道有序相的比较，可以看出C型自旋/G型轨道有序相和G型自旋/C型轨道有序相之间的临界竞争不仅取决于型晶格畸变，而且还取决于离子动量的存在。磁场诱导的自旋/轨道有序相变是伴随着和的极化矩实现的。对于，通过施加约3 T的中等磁场，G-型自旋/C-型轨道有序相被切换到C-型自旋/G-型轨道有序相。相比之下，G-型自旋/C-型轨道排序是相当有利的磁场下。这些结果不能用自旋和离子矩之间的交换相互作用来唯一解释。这种场致相变还可能与动量极化与晶格畸变的耦合有关，晶格畸变与晶格的轨道有序性有关。
We have investigated the spin/orbital phase diagram in the perovskite orthovanadate(, Y, Dy, and Ho) by measurements of magnetization, dielectric constant, specific heat, Raman scattering spectra, and x-ray diffraction, focusing on the interplay between thespin and themoment of theion. The thermally induced phase transition between the C-type spin/G-type orbital ordered state and the G-type spin/C-type orbital ordered state is observed forwithoutmoment. By comparing this phase diagram with the spin/orbital ordering in, it is evident that the critical competition between the C-type spin/G-type orbital ordered phase and the G-type spin/C-type orbital ordered one depends not only on the-type lattice distortion but also on the presence of themoment of theion. The magnetic field induced phase transition of the spin/orbital ordering is achieved concomitantly with polarizingmoments forand. For, the G-type spin/C-type orbital ordered phase is switched to the C-type spin/G-type orbital ordered one by applying a moderate magnetic field around 3 T. By contrast, the G-type spin/C-type orbital ordering is rather favored under the magnetic field in. The results cannot be uniquely explained in terms of the exchange interaction between thespin and the-ionmoment. The coupling of themoment polarization with the lattice distortion tied with the orbital ordering of thesublattice may also be relevant to this field induced phase transition.