Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1596574 | Solid State Communications | 2006 | 6 Pages |
Abstract
To understand the nature of grain boundaries in polycrystalline materials, magneto-transport and ferromagnetic resonance measurement have been performed in polycrystalline La0.6Pb0.4MnO3 (LPMO) thin films prepared by pulsed laser deposition. Films are found to undergo a semiconductor to metal transition at 230Â K and re-enter into the semiconducting state below 130Â K. Microwave absorption measurements carried out as function of applied field show two components of resonant absorption signal. First component is in accordance with ferromagnetic transition of grains at Curie temperature and the second component shows antiferromagnetic transition of grain boundaries at 160Â K. An additional non-resonant absorption signal centered at zero field has also been observed that supports transition from conducting to insulating grain boundaries at â¼160Â K. Further, temperature dependence of resistance in semiconducting state at low temperatures is in accordance with coulomb blockade model indicating insulating nature of AFM grain boundaries.
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Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Ajay Singh, P. Chowdhury, N. Padma, D.K. Aswal, R.M. Kadam, Y. Babu, M.L. Jayanth Kumar, C.S. Viswanadham, G.L. Goswami, S.K. Gupta, J.V. Yakhmi,