Phase transition in quantum tunneling for a parameterized double-well potential
文献类型：期刊论文
| 作者 | Zhou, B ; Liang, JQ ; Pu, FC |
| 刊名 | PHYSICS LETTERS A
 |
| 出版日期 | 2001 |
| 卷号 | 278期号:5页码:243 |
| 关键词 | BIAXIAL SPIN SYSTEM ESCAPE-RATE PERIODIC INSTANTONS CLASSICAL REGIMES FIRST-ORDER DECAY FIELD |
| ISSN号 | 0375-9601 |
| 通讯作者 | Zhou, B (reprint author), Chinese Acad Sci, Inst Phys, POB 603-12, Beijing 100080, Peoples R China. |
| 中文摘要 | Magnetic and transport properties of ultrafine La2/3Ca1/3MnO3 (LCMO) powders synthesized by mechanical alloying with a grain size of about 18 nm have been investigated. It is found that the powder sample is superparamagnetic above 95 K. The blocking temperature (T-B) Obtained from the characteristic peak in the zero-field-cooled magnetization decreases with the measuring applied field, and can be well fitted by T-B = a ln(mu H-0) - b. The spontaneous magnetization of the powder sample is only 38% of that in the corresponding bulk LCMO. Unlike conventional bulk LCMO, the powder compact is insulating from 5 K to 300 K. The low-temperature magnetoresistance (MR), defined as MR = DeltaR/R(0) (R(0) being the zero-field resistance), is approximately 100% under a field of 6 T, much higher than that of the conventional bulk LCMO (50-60%). When the temperature is above T-B, the low-field MR associated with the spin-polarized tunnelling between grains cannot be observed; however, the high-field MR increases linearly with the applied field. The small grain size and the surface layer in which many oxygen vacancies and defects induced by high-energy milling exist are suggested to be responsible for the present observations. |
| 收录类别 | SCI |
| 语种 | 英语 |
| 公开日期 | 2013-09-24 |
| 源URL | [http://ir.iphy.ac.cn/handle/311004/50825]  |
| 专题 | 物理研究所_物理所公开发表论文_物理所公开发表论文_期刊论文 |
| 推荐引用方式 GB/T 7714 | Zhou, B,Liang, JQ,Pu, FC. Phase transition in quantum tunneling for a parameterized double-well potential[J]. PHYSICS LETTERS A,2001,278(5):243. |
| APA | Zhou, B,Liang, JQ,&Pu, FC.(2001).Phase transition in quantum tunneling for a parameterized double-well potential.PHYSICS LETTERS A,278(5),243. |
| MLA | Zhou, B,et al."Phase transition in quantum tunneling for a parameterized double-well potential".PHYSICS LETTERS A 278.5(2001):243. |
入库方式： OAI收割
来源：物理研究所
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