Low-temperature magnetic relaxation in YBa2Cu3O7- delta : Evidence for quantum tunneling of vortices.
Low-temperature magnetic relaxation in YBa2Cu3O7- delta : Evidence for quantum tunneling of vortices.
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DOI：
10.1103/physrevb.43.8709
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发表时间：
1991-04
期刊：
影响因子：
--
通讯作者：
Fruchter;Malozemoff;Campbell;Sánchez;Konczykowski;Griessen;Holtzberg
中科院分区：
文献类型：
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作者：
Fruchter;Malozemoff;Campbell;Sánchez;Konczykowski;Griessen;Holtzberg
${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ 晶体在 0.1--1 K 范围内的霍尔探针测量显示出与温度无关的时间对数磁弛豫。这些结果排除了传统的热激活通量蠕变，如果在简单的一维模型中考虑势垒对驱动力的依赖性，则预测最低温度下的 ${\mathit{T}}^{2/3}$ 依赖性。它们与假设涡旋扭结运动的量子隧道过程的唯象理论是一致的。
Hall-probe measurements of an ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ crystal in the range 0.1--1 K show a temperature-independent time-logarithmic magnetic relaxation. These results rule out conventional thermally activated flux creep, which predicts a ${\mathit{T}}^{2/3}$ dependence at the lowest temperatures if one takes into account the dependence of the barrier on driving force in a simple one-dimensional model. They are consistent with a phenomenological theory assuming a quantum tunneling process for vortex kink motion.