Colossal magnetoresistance

About: Colossal magnetoresistance is a research topic. Over the lifetime, 3658 publications have been published within this topic receiving 130104 citations.

Magnetic properties and colossal magnetoresistance of the perovskites La2/3Ca1/3Mn1−xTixO3

Abstract: Structure, magnetic, and transport properties of the compounds La2/3Ca1/3Mn1-xTixO3(0 less than or equal to x less than or equal to 0.3) have been investigated. The substitution of a Ti4+ ion for a Mn4+ ion suppresses the ferromagnetism and metallic conduction significantly. In the case of low doping (x less than or equal to 0.04), Curie temperature T-C decreases linearly with the substitution at a rate of about 31 K for 1% Ti. The magnetic spontaneous state has become a cluster glass state for the sample where x = 0.06. Corresponding to the decrease of T-C, the metal-insulator transition temperature and the peak of magnetoresistance (MR) shift to low temperature, while the resistivity and the maximum of MR increase with increasing Ti concentration. The magnetic dilution should be responsible for the experimental results. (C) 2000 American Institute of Physics. [S0021-8979(00)41608-7].

Low-field magnetoresistance of La0.7Sr0.3MnO3 thin films with gradually changed texture

Abstract: A gradual change of the grain orientation with the substrate temperature (TS) during deposition has been observed for La0.7Sr0.3MnO3 films on Y-stabilized ZrO2(100) substrates. Epitaxial growth has been found around TS≈800 °C. Both the low-field and the high-field magnetoresistance (MR) observed for the ferromagnetic state of these polycrystalline colossal MR manganite films were found to systematically depend on the degree of texture. The experimental results suggest a crucial role of a highly resistive region at the grain boundaries for this MR effect.

Magnetic field induced properties of manganite perovskites with colossal magnetoresistance (invited)

Abstract: We present a systematic study of the magnetotransport and magnetic properties of the half-doped La0.5Ca0.5MnO3+δ system. The solid is a metamagnet which undergoes a first-order antiferromagnet (AFM) to ferromagnet (FM) phase transition under a field or by changing temperature. Associated with the AFM–FM transition is an insulator to metal transition. A maximum 109-fold magnetoresistance ratio has been observed at 4.2 K between the least and the most conductive states. At low T (⩽50 K), we have also observed two additional metastable electronic states in the canted AFM state at certain fields. The resistivity of each state differs from one another by at least one order of magnitude. The existence of these multiple states may be related to the unique charge- and spin-ordered state of the half-doped manganite.

1/f electrical noise in epitaxial thin films of the manganite oxides La0.67Ca0.33MnO3 and Pr0.67Sr0.33MnO3

Abstract: We report measurements of 1/f electrical noise in two hole doped manganite perovskite oxides, La0.67Ca0.33MnO3 and Pr0.67Sr0.33MnO3, which exhibit colossal magnetoresistance. The noise magnitude represented by the Hooge parameter is nearly 8 orders of magnitude larger than that observed in ordinary metals (and semiconductors) and nearly 5–6 orders of magnitude larger than that observed in epitaxial films of the perovskite oxide YBa2Cu3O7 in the normal state. The normalized noise spectral density increases with decreasing temperature below the resistivity peak, suggestive of the presence of additional low energy noise processes in the ferromagnetic metallic state.