Origin of negative magnetoresistance in polycrystalline SnO2films

Abstract

Recently observed quantum corrections to the conductivity of SnO 2 films suggest the existence of extended states and thus raise the question about the presence and mechanism of a metal-insulator transition. We present a comparative analysis of negative magnetoresistance, observed in fields up to 52 T on SnO 2 polycrystalline films, performed in the frame of both hopping conduction model and quantum corrections to the conductivity model, with the purpose to establish the ranges of agreement between these models and the obtained data. Our results suggest that the observed negative magnetoresistance of SnO 2 films is due to corrections stemming from the weak localization and electron-electron interaction.

Metal-semiconductor transition and negative magneto-resistance in degenerate ultrathin tin oxide films

“…7. It may be noted that all the three samples show a negative MR, and its magnitude increases with decrease in temperature at a field of about 0.9 T. A maximum MR of 1.5% is obtained for a 10 nm thick film at 18 K. The MR in a nonmagnetic semiconductor can be attributed to several effects, including WL effects [7,9,15] weak anti-localization effects [9], electroneelectron interactions [7,15], and superconducting fluctuation effects [20,21]. The weak anti-localization effects and superconducting fluctuation effects are known to always result in positive MR, while the WL effect results in negative MR. Electroneelectron interaction (EEI) manifests itself in the presence of higher magnetic fields than the WL does [7], and in the present case, the MR is observed in the relatively low magnetic field (B 1 T).…”

“…On the contrary, undoped SnO 2 thin films were found to show the classical semiconducting behavior [13,14] at thicknesses above and below 100 nm. The magneto-transport properties of non-magnetic SnO 2 thin films have so far been reported by two groups [11,15]. In one case the observed negative magneto resistance (eMR) of 0.8% at 2e8 K in 200 nm thick undoped non-degenerate SnO 2 films was ascribed to a 2-D like electron transport [15] while in the other case of 650 nm F-doped SnO 2 films a eMR at 12e36 K is attributed to 3-D like electron transport [11].…”

Weak localization and size effects in thin In 2 O 3 films prepared by autowave oxidation

“…Al doped ZnO films grown by atomic layer deposition also had a negative magnetoresistance [15]. Other thin TCO films such as indium tin oxide [16][17][18], B-doped ZnO [19], phosphorus-doped ZnO [20] and tin oxide [21,22] demonstrated a similar dependence of magnetoresistance on a magnetic field.…”

Charge transport inHoxLu1−xB12: Separating positive and negative magnetoresistance in metals with magnetic ions

“…Over the past two decades a number of materials with large MR, such as organic semiconductors [10,11], pregraphitic carbon nanofibers, hydrogenated and fluorinated graphene [12][13][14], amorphous Si doped with magnetic rare-earth ions [15] and bulk germanium doped by multiply charged impurities [16], SnO 2 [17], silver chalcogenides [4,18,19], zero-bandgap Hg 1−x Cd x Te [20], and frustrated metallic ferromagnets [21], which are characterized by extreme field sensitivity and/or large values of MR, have been studied in detail, because of their potential for technological applications such as magnetic sensors and/or magnetoresistive reading heads in magnetic recording [22]. Special attention has been paid also to several types of compounds with magnetic d or f ions having "colossal" negative magnetoresistance (CMR) such as manganites [23,24] and cobaltites [25], double perovskites [26], europium-based hexaborides [27], manganese oxide pyrochlores [3,28], Cr-based chalcogenide spinels [29,30], chromium dioxides [31], GdSi [32], MnSi [33], CeB 6 and * nes@lt.gpi.ru CeAl 2 [34,35], and Zintl compound Eu 14 MnBi 11 [36], where the MR reaches its largest value near ferro-or antiferromagnetic phase transitions and is quite temperature dependent in this region.…”