Characterization of the Mysterious High Field Ordered Phase around H // [111] and Finding of a New Phase Boundary in PrFe4P12
Characterization of the Mysterious High Field Ordered Phase around H // [111] and Finding of a New Phase Boundary in PrFe4P12
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H 周围神秘高场有序相的表征 // [111] 并发现 PrFe4P12 中的新相边界
DOI：
10.1143/jpsj.81.084703
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
H. Aoki
中科院分区：
文献类型：
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作者：
Y. Utsumi;H. Sato;T. Yamashita;S. Ohara;K. Mimura;S. Motonami;K. Shimada;M. Arita;S. Ueda;Y. Yamashita;H. Yoshikawa;K. Kobayashi;H. Namatame;M. Taniguchi;T. Adachi;阿曽尚文;H. Aoki
本文研究了方钴矿PrFe_4P_（12）在[111]轴附近的电阻率ρ和霍耳电阻率ρ霍夫随温度T ~（30）mK和磁场H ~（17.9）T的变化。在低温下，我们在8 T左右接近H [111]的有限场方向范围内观察到ρ（H）和ρH（H）的明显异常，反映了先前报道的高场有序相（HOP）的开始。ρ在（110）面内随场方向的变化呈现出一个坑状结构，在[111]轴附近有一个最小值。磁电阻在低场标量阶相位（SOP）和HOP的边界上表现出明显的异常。随着温度的降低，SOP的高场侧和HOP的低场侧的相边界的方法比以前推断的更慢。由ρ和ρ H测量得到的HOP中的载流子密度比SOP中的载流子密度高一个数量级以上，这排除了outq=（0，0，1）作为HOP的有序波矢量。在HOP内，我们发现了一个额外的异常，并在低于0.75 K的17 T左右出现明显的滞后，表明存在新的相边界。在HOP中附加态的存在可能表明HOP中包含几乎退化的多个内部自由度。这一发现将为阐明HOP的性质和起源提供重要线索。
We have investigated the electrical resistivity ρ and Hall resistivity ρHof the filled skutterudite PrFe4P12as functions of both temperatureTdown to 30 mK and magnetic fieldHup to 17.9 T for the field directions near the [111] axis. At low temperatures, we observed a clear anomaly in ρ(H) and ρH(H) within a limited range of field directions close toH∥[111] at around 8 T, reflecting the onset of the high-field ordered phase (HOP) reported previously. ρ exhibits a crater like structure as a function of the field direction in the (\bar110) plane with a minimum near the [111] axis. Magnetoresistance exhibits clear anomalies across the boundaries of both the low-field scalar-order phase (SOP) and the HOP. With decreasing temperature, the phase boundaries of the high-field side of the SOP and the low-field side of the HOP approach more slowly than was inferred previously. The carrier density in the HOP evaluated by the ρ and ρHmeasurements is more than an order of magnitude higher than that in the SOP, which rules outq= (0,0,1) as the ordering wave vector for the HOP. Within the HOP, we found an additional anomaly accompanied by a clear hysteresis at around 17 T below ∼0.75 K, indicating the existence of a new phase boundary. The existence of the additional state in the HOP may indicate that almost-degenerate multiple internal degrees of freedom are involved in the HOP. This finding should provide an important clue to clarify the nature and origin of the HOP.