Dynamical crossover in 'hot' spin ice

被引：91

作者：

Ehlers, G

Cornelius, AL

Orendác, M

Kajnaková, M

Fennell, T

Bramwell, ST

Gardner, JS ^{[1
]}

机构：

[1] Natl Res Council Canada, Chalk River Labs, Chalk River, ON K0J 1J0, Canada

[2] Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France

[3] Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA

[4] Safarik Univ, Dept Expt Phys, Kosice 04154, Slovakia

[5] UCL Royal Inst Great Britain, London W1X 4BS, England

[6] UCL, Dept Chem, London WC1H 0AJ, England

来源：

JOURNAL OF PHYSICS-CONDENSED MATTER | 2003年 / 15卷 / 02期

关键词：

D O I：

10.1088/0953-8984/15/2/102

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

The magnetic dynamics of the spin ice material Ho2Ti2O7 in its paramagnetic (`hot') phase have been investigated by a combination of neutron spin echo and ac-susceptibility techniques. Relaxation at high temperatures (T > 15 K) is proved to occur by a thermally activated single-ion process that is distinct from the process that dominates at lower-temperatures (1 K < T < 15 K). It is argued that the low-temperature process must involve quantum mechanical spin tunnelling, as quasi-classical channels of relaxation are exhausted in this temperature range. Our results resolve a mystery in the physics of spin ice: why has a 15 K ac-susceptibility peak been observed in Dy2Ti2O7 but not in Ho2Ti2O7 or Ho2Sn2O7?

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页码：L9 / L15

页数：7

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