Magnetization (M) and neutron diffraction measurements have been carried out on a polycrystalline Sc2Fe3Si5-type Tb2Mn3Si5 compound (space group P4/mnc) in the temperature range of 1.8-300 K. The compound undergoes a transition from a room temperature paramagnetic phase to a ferromagnetic phase at 89 K (TC1). A Curie-Weiss type behaviour is observed in the paramagnetic region at temperatures above 150 K. In this compound, both the rare earth (Tb) and Mn ions carry magnetic moments and there are two Mn magnetic sublattices, one coupling ferromagnetically and the other coupling antiferromagnetically with that of rare earth. © 2002 Elsevier Science B.V. All rights reserved.

Sankaranarayanan V

Department Of Physics

R. Nirmala

Kanikrishnan Sethupathi

Antiferromagnetism

Crystal lattices

Ferromagnetism

Magnetic moments

Magnetization

Neutron diffraction

Paramagnetism

Polycrystalline materials

MAGNETIC STRUCTURES

Terbium compounds

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IIT Madras

Magnetic structure of Tb2Mn3Si5

Journal of Alloys and Compounds

The compound Ho2 Mn3 Si5 exhibits multiple magnetic transitions: (i) an ordering at ∼78 K, (ii) a second magnetic transition at ∼16 K, and (iii) an anomaly at ∼4 K. Its paramagnetic Curie temperature is found to be small but positive. Assuming a free ion effective paramagnetic moment of 10.6 μB for Ho3+ ion, the effective paramagnetic moment per Mn in this compound is calculated to be 1.73 μB, which indicates the itinerant nature of Mn d electrons. The various transitions in magnetization data are perhaps due to the ordering of rare earth and Mn moments. The magnetization at 2 K in applied fields of up to 7 T has linear field dependence, indicating dominant antiferromagnetic interactions in the system. Neutron diffraction studies point to a complex amplitude modulated incommensurate magnetic structure at 9 K. © 2009 American Institute of Physics.

Fulltext

Journal of Applied Physics

Competing magnetic interactions in the intermetallic compound Ho2 Mn3 Si5

Magnetization measurements have been carried out on the Er2Mn3Si5 compound (tetragonal Sc2Fe3Si5-type, space group P4/mnc) in the temperature range 1.8-300 K. There is a crossover from a room temperature paramagnetic phase to a ferromagnetic phase at 75 K (TC1). A second magnetic transition is observed at 11.5 K (TC2). The magnetic susceptibility in the paramagnetic region, above 100 K, follows simple Curie-Weiss type behavior. The magnetization does not saturate at 2 K even in applied fields of 7 T. Neutron diffraction data collected at 300 and 9.2 K confirm that both the rare earth and the Mn moments in this compound carry magnetic moments. There are two Mn sublattices (Mn1 and Mn2) coupled orthogonal to each other. Both the rare earth and the Mn1 sublattice order along the positive a axis but the Mn2 moments order along the positive c axis, thus leading to a competition of magnetic interactions at low temperatures. © 2002 Elsevier Science B.V. All rights reserved.

Magnetic properties of Er2Mn3Si5

The results of ac magnetic susceptibility, dc electrical resistivity and thermoelectric power measurements on Tb2Mn3Si5 compound of Sc2Fe3Si5-type structure are reported in the temperature range 20-300 K. The compound is a paramagnet at room temperature and it undergoes a para- to ferrimagnetic transition at around 172±0.5 K (TC1) and enters the ferromagnetic region around 30±0.5 K (TC2). The resistivity shows an insulator to metal-type transition as the material goes from the disordered paramagnetic phase to the ordered magnetic phase. The thermopower is negative at room temperature and it crosses zero at around 132 K displaying a broad maximum centered at 65 K. These successive magnetic transitions are attributed to competitive Mn-Mn inter- and intralayer interactions, characteristic of the layered structure of the compound.

Multi-magnetic transitions in Tb2Mn3Si5

Author Index of Volume 325

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. © 1996 American Institute of Physics.

Applied Physics Letters

Positive giant magnetoresistance in antiferromagnetic RE2Ni3Si5 (RE=Tb, Sm, Nd)

Physica B: Condensed Matter

Recent advances in magnetic structure determination by neutron powder diffraction

The results of electrical resistivity (4.2-300 K), magnetic susceptibility (5-300 K) and specific heat (2-20 K) are reported on the ternary orthorhombic rare-earth compound Ce2Ni3Si5. The resistivity of the material is nearly temperature independent above 120 K unlike that of a normal metallic material. The magnetic contribution to resistivity shows a broad maximum around 200 K. At low temperatures, the resistivity follows a T2 behavior in the temperature range 4-13 K. The inverse magnetic susceptibility deviates from Curie-Weiss behavior below 80 K where it exhibits a broad maximum in the χ vs T curve. Specific heat measurements (2-20 K) give a value of γ62 mJ/Ce mol K2 which is similar in magnitude to those encountered in valence-fluctuating systems. From these observations we conclude that Ce2Ni3Si5 is a Ce-based valence-fluctuation compound. © 1992 The American Physical Society.

Physical Review B

Ce2Ni3Si5: A mixed-valence cerium compound

Journal	Journal of Alloys and Compounds
ISSN	09258388
Open Access	No