Related papers: Magnetoresistance in Mn pyrochlore: electrical tra…
Neutron scattering has been used to study the magnetic order and spin dynamics of the colossal magnetoresistive pyrochlore Tl_2Mn_2O_7. On cooling from the paramagnetic state, magnetic correlations develop and appear to diverge at T_C (123…
We present a small-but-sizeable magnetic polaron picture where transport at high temperatures is activated while at low temperatures it is band-like. We show that both double exchange and finite bandwidth effects are important to understand…
Polycrystalline La$_{2/3}$Sr$_{1/3}$MnO$_{3}$ (LSMO) thin films were synthesized by pulsed laser ablation on single crystal (100) yttria-stabilized zirconia (YSZ) substrates to investigate the mechanism of magneto-transport in a granular…
We report measurements of the resistivity in the ferromagnetic state of epitaxial thin films of La_{1-x}Ca_{x}MnO_{3} and the low temperature specific heat of a polycrystalline La_{0.8}Ca_{0.2}MnO_{3}. The resistivity below 100 K can be…
This study aims to unravel the mechanism of colossal magnetoresistance (CMR) observed in n-type HgCr$_2$Se$_4$, in which low-density conduction electrons are exchange-coupled to a three-dimensional Heisenberg ferromagnet with a Curie…
Hall resistivity and magneto-thermopower have been measured for colossal magnetoresistive Tl2Mn2O7 over wide temperature and magnetic-field ranges. These measurements revealed that a small number of free electron-like carriers is…
The colossal magnetoresistance exhibited by Tl_{2}Mn_{2}O_{7} is an interesting phenomenon, as it is very similar to that found in perovskite manganese oxides although the compound differs both in its crystalline structure and electronic…
Tl$_{2}$Mn$_{2}$O$_{7}$ pyrochlores present colossal magnetoresistance (CMR) around the long range ferromagnetic ordering temperature (T$_{C}$). The character of this magnetic phase transition has been determined to be first order, by…
We investigate the transport properties of itinerant electrons interacting with a background of localized spins in a correlated paramagnetic phase of the pyrochlore lattice. We find a residual resistivity at zero temperature due to the…
Polycrystalline thin films of double layer manganite La_1.4Ca_1.6Mn_2O_7 (DLCMO) have been deposited by nebulized spray pyrolysis on single crystal LaAlO_3 substrates. These single phase films having grain size in the range 70-100 nm…
The magnetic transport properties have been measured for La0.67-xYxCa0.33MnO3 (0 <= x <= 0.14) system. It was found that the transition temperature Tp almost linearly moves to higher temperature as H increases. Electron spin resonance…
The magnetoresistance (MR) in polycrystalline colossal magnetoresistive compounds follows a behavior different from single crystals below the ferromagnetic transition temperature. This difference is usually attributed to spin polarized…
There have been speculations about the need to find a new mechanism to explain the colossal magnetoresistance exhibited by this material, having pyrochlore structure and thus differing structurally and electronically from the manganites. We…
The transport and magnetic properties in ferromagnetic manganese-oxide thin films are studied based on the model of the coupling between the mobile d-electrons and the core spins in Mn ions. The spontaneous magnetization and the resistivity…
For the first time magnetrotransport of the ferromagnetic high-pressure phases of (GaSb)$_2$M (M=Cr,Mn) was measured. It was found that the main component of magnetotransport in these phases is negative and its amplitude is increasing with…
We present a magnetotransport study of the low--carrier density ferromagnet EuB_6. This semimetallic compound, which undergoes two ferromagnetic transitions at T_l = 15.3 K and T_c = 12.5 K, exhibits close to T_l a colossal…
The magnetic, transport, and structural properties of (Ga,Cr)As are reported. Zincblende Ga$_{1-x}$Cr$_{x}$As was grown by low-temperature molecular beam epitaxy (MBE). At low concentrations, x$\sim$0.1, the materials exhibit unusual…
The magnetization processes of the spin-3/2 antiferromagnet LiInCr4O8 comprising a "breathing" pyrochlore lattice, which is an alternating array of small and large tetrahedra, are studied under ultrahigh magnetic fields of up to 130 T using…
A new mechanism is proposed to explain the colossal magnetoresistance and related phenomena. Moving electrons accompanied by Jahn-Teller phonon and spin-wave clouds may form composite polarons in ferromagnetic narrow-band manganites. The…
Based on the combined model of the double exchange and the polaron, we have studied the small-to-large polaron crossover transition and explored its effects on the magnetic and transport properties in colossal magnetoresistance (CMR)…