Magnetic Phase Diagram in NdCu4Ag Single Crystal

概要

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The magnetic properties of cubic intermetallic compound NdCu4Ag single crystals were studied in detail through magnetization, susceptibility, specific heat and electrical resistivity measurements. An observed anomaly in $C(T)$ with a sharp peak 26 J/(mol K) at 4.2 K, together with an antiferromagnetic behavior of $\chi(T)$, indicated that an antiferromagnetic phase transition occurred at this temperature. Anisotropic properties in $M(H)$, $\chi(T)$, and $C(T)$ at external fields were investigated in directions of [001], [110], and [111], respectively. Two metamagnetic transitions were observed below the Néel temperature $T_{\text{N}}$ when a magnetic field was applied in three directions. In all the three directions, $T_{\text{N}}$ decreased with an increase in magnetic field and new anomalies induced by a high $H_{\text{ext}}$ were observed in both $\chi(T)$ and $C(T)$, implying that two new magnetic phases coexisted with the antiferromagnetic phase. From the specific heat measurements, it is speculated that the crystalline electric field ground state of Nd3+ ($J = 9/2$) ions is the $\Gamma_{8}$ quartet for NdCu4Ag. From these anomalies, the magnetic phase diagram of NdCu4Ag was determined.
2010-04-15