Topic
Colossal magnetoresistance
About: Colossal magnetoresistance is a research topic. Over the lifetime, 3658 publications have been published within this topic receiving 130104 citations.
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TL;DR: Effective kinetic-exchange model calculations in (Ga,Mn)As show chemical potential anisotropies consistent with experiment and ab initio calculations in transition metal systems suggest that this generic effect persists to high temperatures in metal ferromagnets with strong spin-orbit coupling.
Abstract: We observe low-field hysteretic magnetoresistance in a $(\mathrm{Ga},\mathrm{Mn})\mathrm{As}$ single-electron transistor which can exceed 3 orders of magnitude. The sign and size of the magnetoresistance signal are controlled by the gate voltage. Experimental data are interpreted in terms of electrochemical shifts associated with magnetization rotations. This Coulomb blockade anisotropic magnetoresistance is distinct from previously observed anisotropic magnetoresistance effects as it occurs when the anisotropy in a band structure derived parameter is comparable to an independent scale, the single-electron charging energy. Effective kinetic-exchange model calculations in $(\mathrm{Ga},\mathrm{Mn})\mathrm{As}$ show chemical potential anisotropies consistent with experiment and ab initio calculations in transition metal systems suggest that this generic effect persists to high temperatures in metal ferromagnets with strong spin-orbit coupling.
114 citations
TL;DR: A recent vast experimental and theoretical effort in manganites has shown that the magnetoresistance effect can be understood based on the competition of charge-ordered and ferromagnetic phases as discussed by the authors.
114 citations
TL;DR: Sr2CoMoO6 perovskite has been prepared in polycrystalline form by thermal treatment, in air, of previously decomposed citrate precursors as discussed by the authors.
Abstract: Sr2CoMoO6 perovskite has been prepared in polycrystalline form by thermal treatment, in air, of previously decomposed citrate precursors. This material has been studied by X-ray (XRD) and neutron powder diffraction (NPD), thermal analysis, and magnetic, magnetotransport, and Hall effect measurements. At room temperature, the crystal structure is tetragonal with a space group I4/m, with a = 5.565 03(5) and c = 7.948 10(8) A. The crystal contains alternating CoO6 and MoO6 octahedra, tilted by 6.8° in the basal ab plane. Magnetic measurements indicate an antiferromagnetic ordering below TN = 37 K. As prepared, the sample is an electrical insulator. The topotactic reduction of the stoichiometric sample, in H2/N2 flows, leads to oxygen-deficient double perovskites, Sr2CoMoO6-δ, δ = 0.03 and 0.14. The magnetic behavior of the reduced samples suggests the presence of ferromagnetic domains characterized by Curie temperatures of TC = 350−370 K. The conductivity dramatically increases upon H2 reduction; the number ...
114 citations
TL;DR: In this paper, it was found that La2−2xCa1+2xMn2O7 (x=0.25) is a metallic ferromagnet with a magnetic transition temperature Tc of 215 K.
Abstract: Bulk samples of La2−2xCa1+2xMn2O7 with the layered Sr3Ti2O7‐type perovskite structure have been successfully synthesized and investigated with respect to their magnetic and electrical properties. It is found that La2−2xCa1+2xMn2O7 (x=0.25) is a metallic ferromagnet with a magnetic transition temperature Tc of 215 K. The large magnetoresistance (MR) effect with Δρ/ρ0 of ∼60% at 1.8 T was observed in a wide temperature range below a cusp temperature in resistivity of 96 K, which is well below the magnetic Tc. This behavior is quite different from that of the well‐known double‐exchange ferromagnets such as La1−xCaxMnO3, where large MR effects are restricted to a narrow temperature range around the ferromagnetic transition. The present result could be interpreted by using the double‐exchange theory incorporating the anisotropy resulting from the two‐dimensional Mn‐O‐Mn networks in La2−2xCa1+2xMn2O7.
114 citations
TL;DR: The lattice matching template/buffer layer approach is suitable for the high quality CMR films on Si and a close correlation between the magnetic hysteresis loop and the field dependence of MR is observed at lower temperatures as mentioned in this paper.
Abstract: We are able to grow high quality La0.67Sr0.33MnO3(LSMO) colossal magnetoresistive (CMR) thin films on Y‐stabilized zirconia (YSZ) buffered (100) Si substrates using a Bi4Ti3O12 texturing and lattice matching layer. The CMR films have very high structural perfection and show excellent transport and ferromagnetic properties, including the almost full saturation magnetization values and narrow ferromagnetic resonance peaks (15 Oe at 290 K). The lattice matching template/buffer layer approach is suitable for the high quality CMR films on Si. A close correlation between the magnetic hysteresis loop and the field dependence of MR is observed at lower temperatures.
113 citations