Reentrant ferromagnetism in Gd2Mn3Ge5
TL;DR: In this article, preliminary results of AC magnetic susceptibility, DC electrical resistivity and thermopower measurements on the new ternary compound Gd2Mn3Ge5 in the temperature range 15-300 K are reported.
Abstract: Preliminary results of AC magnetic susceptibility, DC electrical resistivity and thermopower measurements on the new ternary compound Gd2Mn3Ge5 in the temperature range 15–300 K are reported. It is a ferromagnet at room temperature and the onset of ferromagnetism is observed around 236 K whereas reentrant ferromagnetism occurs near 88 K. The successive magnetic transitions are attributed to the layered structure of the compound.
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TL;DR: In this article, the magnetic properties of SmMn2Ge2 with a layer structure have been studied by magnetization measurements using single crystal, and the appearance of successive magnetic orderings are attributed to the variation of the shortest Mn-Mn distance due to thermal expansion and the existence of ferromagnetic coupling between the Sm moments in the intralayer which is dominant at low temperatures.
Abstract: Magnetic characteristics of SmMn2Ge2 with a layer structure have been studied by magnetization measurements using single crystal. In the sequence of decreasing temperature, ferromagnetism is observed at 196 K ≲ T ≲ 348 K, collinear antiferromagnetism becomes stable for 64 K ≲ T < 196 K and reentrant ferromagnetism appears below 64 K. The appearance of such successive magnetic orderings are attributed to the variation of the shortest Mn-Mn distance due to thermal expansion and the existence of ferromagnetic coupling between the Sm moments in the intralayer which is dominant at low temperatures.
163 citations
TL;DR: In this paper, positive giant magnetoresistance (GMR) was reported in polycrystalline antiferromagnetic materials RE2Ni3Si5 (RE=Tb, Sm, Nd); Δρ/ρ, at 4.4 K and in a field of 45 kOe, is 85%, 75%, and 58%, respectively.
Abstract: Positive giant magnetoresistance (GMR), Δρ/ρ, is reported here in polycrystalline antiferromagnetic materials RE2Ni3Si5 (RE=Tb, Sm, Nd); Δρ/ρ, at 4.4 K and in a field of 45 kOe, is 85%, 75%, and 58%, respectively. Positive GMR of such large magnitude has not been reported earlier in magnetically ordered polycrystalline compounds. The observed GMR is not correlated to the RE‐moments. It is, however, associated with the magnetic ordering of the lattice as its magnitude is significantly reduced in the paramagnetic state. Surprisingly, MR in Y2Ni3Si5, a non‐magnetic rare earth analogue, is also relatively large (16% at 4.4 K; 45 kOe) and is even slightly higher than that of antiferromagnetically ordered Gd2Ni3Si5 (12% at 4.4 K; 45 kOe). The layered structure of the materials is suggested to be responsible for the observed GMR.
44 citations
TL;DR: In this article, the formation of two new materials, Sm2Ni3Si5 and Gd2Ni 3Si5, of the rare earth series R2M3 Si5 (R denotes rare earth and Y) and their magnetic and transport properties are reported.
Abstract: The formation of two new materials, Sm2Ni3Si5 and Gd2Ni3Si5, of the rare‐earth series R2M3Si5 (R denotes rare earth and Y) and their magnetic and transport properties are reported here. These materials crystallize in the orthorhombic U2Co3Si5‐type structure (space group Ibam). The magnetic susceptibility of Gd2Ni3Si5 follows a Curie–Weiss behavior with an effective magnetic moment 8.1μB/Gd ion. The material orders antiferromagnetically at ≊15 K. The magnetic susceptibility of Sm2Ni3Si5 exhibits a deviation from the Curie–Weiss behavior which is attributed to the low‐lying excited state of Sm3+ ions and also to crystal‐field effects. This material also orders antiferromagnetically, but at ≊11 K. This value of the ordering temperature does not seem to follow the de Gennes scaling with respect to that of Gd2Ni3Si5.
16 citations