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. © 2000 Elsevier Science B.V. All rights reserved.

Sankaranarayanan V

Department Of Physics

R. Nirmala

Kanikrishnan Sethupathi

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Reentrant ferromagnetism in Gd2Mn3Ge5

Physica B: Condensed Matter

The heat capacity of polycrystalline R2 Ti3 Ge4 (R=Gd, Tb, and Er) compounds (orthorhombic, Sm5 Ge4 -type, space group Pnma) has been studied in the temperature range of 1.8-300 K in various applied magnetic fields. The compounds with magnetic lanthanide elements show interesting low field magnetism intrigued by the possible presence of competing antiferromagnetic and ferromagnetic interactions. The magnetocaloric effect in these compounds is estimated from the field dependent heat capacity data. The magnetic entropy change and the adiabatic temperature change in the vicinity of the magnetic transition are found to be significant. © 2008 American Institute of Physics.

Fulltext

Journal of Applied Physics

Magnetocaloric effect in R2 Ti3 Ge4 (R=Gd, Tb, and Er) compounds

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)

The formation of two new materials, Sm2Ni3Si 5 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 Gd 2Ni3Si5 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 Sm 2Ni3Si5 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.

Journal	Data powered by TypesetPhysica B: Condensed Matter
Publisher	Data powered by TypesetElsevier
ISSN	09214526
Open Access	No