Metamagnetism, giant magnetoresistance and magnetocaloric effects in RCO2-based compounds in the vicinity of the Curie temperature
Metamagnetism, giant magnetoresistance and magnetocaloric effects in RCO2-based compounds in the vicinity of the Curie temperature
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DOI：
10.1016/s0921-4526(02)01099-2
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发表时间：
2002-07-01
影响因子：
2.8
通讯作者：
Brommer, PE
中科院分区：
文献类型：
--
作者：
Duc, NH;Anh, DTK;Brommer, PE
测量了（R，R '）Co-2，（R，Y）Co-2和R（Co，Si）（2）（R，R' =稀土）化合物的磁化和磁电阻等温线。在具有一级相变的化合物（即ErCo 2-、HoCo 2-和DyCo 2-基化合物）的居里温度（T-C）之上观察到变磁转变。4f-和3d-亚晶格磁矩都有助于在此过渡的磁化强度的急剧变化。磁阻的同时抑制可以被认为是由于自旋涨落的猝灭。此外，通过使用麦克斯韦方程从磁化数据估计磁熵变Δ S（m）。由此产生的巨磁热效应的4f（R）-本地化的自旋和3d（Co）-自旋波动以及相变的性质进行了讨论。(C)2002 Elsevier Science B. V.保留所有权利。
Magnetisation and magnetoresistance isotherms were measured for a number of (R,R')Co-2, (R,Y)Co-2 and R(Co,Si)(2) (R,R' = rare earth) compounds. A metamagnetic transition is observed just above the Curie temperature (T-C) of compounds having a first order phase transition, i.e. ErCo2-, HoCo2-, and DyCo2-based ones. Both 4f- and 3d-sublattice magnetic moments contribute to a sharp change of the magnetisation at this transition. The concurring suppression of the magneto resistance can be considered to be due to quenching of spin fluctuations. In addition, the magnetic entropy change DeltaS(m) is estimated from the magnetisation data by using a Maxwell equation. The resulting giant magnetocaloric effects are discussed in terms of the 4f(R)-localised spin and the 3d(Co)-spin fluctuations as well as the nature of the phase transition. (C) 2002 Elsevier Science B.V. All rights reserved.