论文标题
弱的pyrochlore阶段的出现和场的签名在dy $ _ {2-x} $ la $ _ {x} $ zr $ _ {2} $ o $ $ $ _ {7} $; x = 0，0.15，0.3
Emergence of weak pyrochlore phase and signature of field induced spin ice ground state in Dy$_{2-x}$La$_{x}$Zr$_{2}$O$_{7}$; x = 0, 0.15, 0.3
论文作者
论文摘要
pyrochlore氧化物dy $ _ {2} $ ti $ _ {2} $ o $ $ _ {7} $和HO $ _ {2} $ _ {2} $ ti $ _ {2} $ _ {2} $ $ $ $ _ {7} $是经过精心研究的旋转冰系统，并且已经显示出磁性单调降级的结果。与这些不同，dy $ _ {2} $ zr $ _ {2} $ o $ $ _ {7} $报告在畸变的氟矿结构中结晶。我们在这里提出了la替换的磁和热容量研究dy $ _ {2} $ zr $ _ {2} $ o $ $ _ {7} $。我们的发现表明，在dy $ _ {2} $ zr $ _ {2} $ o $ $ $ _ {7} $中缺乏旋转冰状状态，但是磁场的出现在t $ 10 k易于敏感性测量的t $ 10 k接近$ 10 k的旋转中，与dy $ _ {2} $ _ {2} $ ti $ ti $ _ $ _} $ _ {2 $ _} dy $ _ {2} $ zr $ _ {2} $ o $ _ {7} $的磁热容量显示峰位置从零场的1.2 k转移到磁场中的较高温度，磁性熵的相应下降。 5 KOE场的低温磁熵是RLN2-（1/2）RLN（3/2），与自旋冰状态相同。代替非磁性，iSovalent la $^{3+} $替换为Dy $^{3+} $逐渐引起从高度无序的荧光岩到弱有序的pyrochlore阶段的结构变化。 La $^{3+} $以较少扭曲的pyrochlore相位的化合物显示了较低场的自旋冷冻，这在磁场的应用中进一步增强。我们的结果表明，旋转冰状态可以通过DY $ _ {2} $ zr $ _ {2} $ o $ $ $ _ {7} $稳定，或者通过在系统中的合适替换来加强旋转动力学或通过合适的替换来增强Pyrochlore阶段。
The pyrochlore oxides Dy$_{2}$Ti$_{2}$O$_{7}$ and Ho$_{2}$Ti$_{2}$O$_{7}$ are well studied spin ice systems and have shown the evidences of magnetic monopole excitations. Unlike these, Dy$_{2}$Zr$_{2}$O$_{7}$ is reported to crystallize in a distorted fluorite structure. We present here the magnetic and heat capacity studies of La substituted Dy$_{2}$Zr$_{2}$O$_{7}$. Our findings suggest the absence of spin ice state in Dy$_{2}$Zr$_{2}$O$_{7}$ but the emergence of the magnetic field induced spin freezing near T $\approx$ 10 K in ac susceptibility measurements which is similar to Dy$_{2}$Ti$_{2}$O$_{7}$. The magnetic heat capacity of Dy$_{2}$Zr$_{2}$O$_{7}$ shows a shift in the peak position from 1.2 K in zero field to higher temperatures in the magnetic field, with the corresponding decrease in the magnetic entropy. The low temperature magnetic entropy at 5 kOe field is Rln2 - (1/2)Rln(3/2) which is same as for the spin ice state. Substitution of non-magnetic, isovalent La$^{3+}$ for Dy$^{3+}$ gradually induces the structural change from highly disordered fluorite to weakly ordered pyrochlore phase. The La$^{3+}$ substituted compounds with less distorted pyrochlore phase show the spin freezing at lower field which strengthens further on the application of magnetic field. Our results suggest that the spin ice state can be stabilized in Dy$_{2}$Zr$_{2}$O$_{7}$ either by slowing down of the spin dynamics or by strengthening the pyrochlore phase by suitable substitution in the system.
