Low temperature magnetoresistance in La1.32Sr1.68Mn2O7 layered manganite under hydrostatic pressure

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:322

Article

Kumaresavanji, M.¹  Fontes, M. B.¹ 

[1] CBPF, Rio De Janeiro, Brazil

关键词: Tunneling magnetoresistance;    Layered manganite;    Magnetic tunnel junction;    Hydrostatic pressure;   

DOI  :  10.1016/j.jmmm.2010.02.037

来源: Elsevier

【 摘 要 】

The La1.32Sr1.68Mn2O7 layered manganite system has been studied by the low temperature electrical resistance and magnetoresistance under hydrostatic pressure up to 25 kbar. We have observe both, a Curie temperature (T-C) and a metal-insulator transition (T-MI) at 118 K in the ambient pressure. The applied pressure shifts the T-MI to higher temperature values and induces a second metal-insulator transition (T-MI(2)) at 90 K, in the temperature dependence of resistivity measurements. Also, the pressure suppresses the peak resistance abruptly at T-C. When an external field of 5 T is applied, we have observed a large negative magnetoresistance of 300% at the transition temperature and a 128% at 4.5 K. However, the increased pressure decreases the magnetoresistance ratio gradually. When the pressure reaches its maximum available value of 25 kbar, the magnetoresistance ratio decreases at a rate of 1.3%/kbar. From our experimental results, the decrease of magnetoresistance ratio with pressure is explained by the pressure induced canted spin state which is not favor for the spin polarized intergrain tunneling in layered manganites. (C) 2010 Elsevier B.V. All rights reserved.

【 授权许可】

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