Magnetocaloric effect study on the pyrochlore spin ice compound Dy2Ti2O7 in a [111] magnetic field
Magnetocaloric effect study on the pyrochlore spin ice compound Dy2Ti2O7 in a [111] magnetic field
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DOI：
10.1143/jpsj.73.2851
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发表时间：
2004-10-01
影响因子：
1.7
通讯作者：
Hiroi, Z
中科院分区：
文献类型：
--
作者：
Aoki, H;Sakakibara, T;Hiroi, Z
在平行于[111]的磁场H中，通过磁热效应测量研究了自旋冰化合物Dy_2 Ti_2 O_7的熵S（H）随磁场的变化，并着重研究了冰规则打破的自旋翻转转变.在T = 0.35 K时，S（H）在可果美冰态下出现一个平台，直到接近0.8 T，然后在0.9 T时急剧下降，此时发生向饱和态的一级相变。在略高于临界点（T-cr = 0.36K）的温度下，S（H）在0.4K和0.5K的自旋翻转场（约0.9T）处出现一个明显的峰，表明在自旋翻转场中存在“两进两出”和“三进一出”态，从而增强了简并度。然而，S（H）的峰值高度是强烈的温度依赖性，并大大小于预期的最近邻自旋冰模型，表明在系统中存在一定的磁相关。
Field variation of the entropy S(H) of the spin ice compound Dy2Ti2O7 has been examined by means of magnetocaloric effect measurements in a magnetic field H parallel to [111], with attention focused on the ice-rule breaking spin-flip transition. At T = 0.35 K, S(H) exhibits a plateau in the kagome ice state up to similar to0.8 T, followed by a sharp decrease at 0.9 T where a first-order transition to the saturated state occurs. Slightly above the critical point of the transition (T-cr similar or equal to 0.36 K), S(H) at 0.4 K and 0.5 K exhibits a pronounced peak at the spin flip field of similar to0.9 T indicating an enhanced degeneracy due to coexistence of "two-in, two-out" and "three-in, one-out" states at the field. The peak height of S(H) is, however, strongly temperature dependent and substantially smaller than that expected from a nearest-neighbor spin ice model, suggesting the presence of certain magnetic correlation in the system.