High-magnetic-field study of the phase transitions of R1-xCaxMnO3 (R = Pr, Nd)
High-magnetic-field study of the phase transitions of R1-xCaxMnO3 (R = Pr, Nd)
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DOI：
10.1103/physrevb.57.5259
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发表时间：
1998-03-01
影响因子：
3.7
通讯作者：
Tokura, Y
中科院分区：
文献类型：
--
作者：
Tokunaga, M;Miura, N;Tokura, Y
我们研究了磁场诱导的相变R1-xCaxMnO 3（R=Pr和Nd，x = 0.50，0.45和0.50，0.45，0.40）的磁化强度，磁阻，和磁致伸缩利用一个非破坏性的长脉冲磁铁（产生高达40 T）的测量。我们观察到的过程中，磁场破坏的实空间有序的电荷载流子，并导致绝缘体到金属的相变在整个温度区域低于约250 K。我们发现，电荷有序的破坏伴随着结构相变，以及与磁相变和庞磁电阻效应。温度与过渡场曲线的不同轮廓取决于载流子浓度x，可以归因于公度和非公度电荷有序态之间的熵的差异。结果表明，电荷有序态的稳定性与局域Mn磁矩的共线反铁磁有序性密切相关。
We have investigated the magnetic-field-induced phase transitions of R1-xCaxMnO3 (R=Pr and Nd, x = 0.50, 0.45 and 0.50, 0.45, 0.40) by measurements of magnetization, magnetoresistance, and magnetostriction utilizing a nondestructive long-pulse magnet (generating up to 40 T). We observed processes where magnetic fields destroy the real-space ordering of the charge carriers and cause insulator-to-metal phase transitions over the whole temperature region below about 250 K. We found that the destruction of the charge ordering is accompanied with a structural phase transition as well as with the magnetic phase transition and the colossal magnetoresistance effect. The different profiles of the temperature vs transition field curve depending on the carrier concentration x may be ascribed to the difference in the entropy between the commensurate and the discommensurate charge-ordered state. It turned out that the stability of the charge-ordered state is strongly correlated with the colinear antiferromagnetic ordering of the localized Mn moments.