Effects of magnetic field on the pseudogap in the Kondo semiconductor CeRhAs
Effects of magnetic field on the pseudogap in the Kondo semiconductor CeRhAs
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DOI：
10.1016/j.jmmm.2003.12.326
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发表时间：
2004-07
影响因子：
2.7
通讯作者：
S. Yoshii;K. Kindo;T. Sasakawa;T. Suemitsu;T. Takabatake
中科院分区：
文献类型：
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作者：
S. Yoshii;K. Kindo;T. Sasakawa;T. Suemitsu;T. Takabatake
单晶 CeRhAs（即能隙为 ∼280 K 的近藤半导体）的磁化强度和磁阻已在高达 55 T 的脉冲磁场中测量。在 1.3 K 时，H || 的磁化强度 M 的斜率b 和 H || c 分别在 16 T 和 13 T 左右略有下降，而 M(H || a) 表现出单调依赖性。整体上观察到弱各向异性，Mb(H)>Mc(H)>Ma(H)。 Mb(H)仅达到0.07 μB/ f.u. 在 55 T 时，这表明即使在高磁场中也保持稳定的非磁性状态。在磁阻中观察到强各向异性行为。沿 b 轴和 c 轴的纵向磁阻 (LMR) 显示出部分与磁化异常相关的特征结构，而沿 a 轴的 LMR 仅显示出较宽的最大值。 I || 的横向磁阻 (TMR) b 和我 || c 遵循关系 Δ ρ(H)/ρ(0)∝Hα(α=1.5 –1.7) 低于 5 T ，而 I || 的 TMR a 仅表现出弱场依赖性。这些结果表明在态密度的宽赝能隙结构中存在狭窄且各向异性的结构。
The magnetization and magnetoresistance of single-crystalline CeRhAs, which is the so-called Kondo semiconductor with an energygap of ∼280 K , have been measured in pulsed magnetic field up to 55 T . At 1.3 K , the slopes of the magnetization M for H || b and H || c decrease slightly at around 16 and 13 T , respectively, while M(H || a) shows monotonous dependence. Weak anisotropy is observed on the whole, Mb(H)>Mc(H)>Ma(H). Mb(H) reaches only to 0.07 μB/ f.u. at 55 T , which indicates the non-magnetic state being stable even in the high magnetic field. Strongly anisotropic behaviors are observed in the magnetoresistance. The longitudinal magnetoresistance (LMR) along the b- and c-axis show characteristic structures partly associated with the anomalies of the magnetizations, while the LMR along the a-axis shows only a broad maximum. The transverse magnetoresistances (TMR) for I || b and I || c follow the relation Δ ρ(H)/ρ(0)∝Hα(α=1.5 –1.7) below 5 T , whereas TMR for I || a exhibits only the weak field dependence. These results suggest the existence of a narrow and anisotropic structure within the wide pseudogap structure in the density of states.