Physics of grain boundaries in the colossal magnetoresistance manganites

Gross, Rudolf; Alff, Lambert; Büchner, B.; Freitag, Bert; Höfener, C.; Klein, Jacques-Olivier; Lu, Yijia; Mader, W.; Philipp, J. B.; Rao, M. S. Ramachandra; Reutler, P.; Ritter, S.; Thienhaus, Sigurd; Uhlenbruck, Sven; Wiedenhorst, B.

doi:10.1016/s0304-8853(99)00727-1

Cited by 186 publications

(137 citation statements)

References 38 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…Here, GBs can act as tunneling barriers for spin-dependent transport. This variation behavior of double ρ peaks is presumably related to the increase of both the height and width of tunneling barriers with decreasing the grain size [24]. Therefore, the height of the Figure captions Sample A 0T 0.5T…”

mentioning

confidence: 99%

The effect of grain size on electrical transport and magnetic properties of La0.9Te0.1MnO3

Yang

Zhao

Zhang

et al. 2004

Solid State Communications

View full text Add to dashboard Cite

The effect of grain size on structural, magnetic and transport properties in were dissolved in diluted nitric acid in which an excess of citric acid and ethylene glycol was added to make a metal complex. After all the reactants had completely dissolved, the solution was mixed and heated on a hot plate resulting in the formation of a gel. The gel was dried at 250 °C, and then preheated to 600 °C to remove the remaining organic and to decompose the nitrates of the gel. The resulting powder was pressed into pellets, each of which was sintered at a different temperature (T s = 800 °C, 900 °C and 1000 °C) in air. In order to obtain a polycrystalline reference pattern, The crystal structures were examined by x-ray diffractometer using Cu 4 α K radiation at room temperature. The magnetic measurements were carried out with a Quantum Design superconducting quantum interference device (SQUID) MPMS system (2 ≤T≤400 K, 0 ≤ H ≤5 T). Both zero-field-cooling (ZFC) and field-cooling (FC) data were recorded. The resistance was measured by the standard four-probe method from 25 to 300 K. ACKNOWLEDGMENTS

show abstract

mentioning

confidence: 99%

The effect of grain size on electrical transport and magnetic properties of La0.9Te0.1MnO3

Yang

Zhao

Zhang

et al. 2004

Solid State Communications

View full text Add to dashboard Cite

show abstract

“…In order to understand and exploit this effect several studies have used bicrystal grain boundary junctions [6,7,8]. Since bicrystals are samples with well defined crystal orientations with respect to an interface, they are in a way ideal systems for studies of the behaviour of magnetic tunnel junctions.…”

mentioning

confidence: 99%

Stoner–Wohlfarth model applied to bicrystal magnetoresistance hysteresis

Gunnarsson

Hanson

Dubourdieu

2004

Journal of Applied Physics

View full text Add to dashboard Cite

We calculate numerically the magnetization direction as function of magnetic field in the StonerWohlfart theory and are able to reproduce the shape of the low-field magnetoresistance hysteresis observed in manganite grain boundary junctions. Moreover, we show that it is necessary to include biaxial magnetocrystalline anisotropy to fully describe the grain boundary magnetoresistance in La0.7Sr0.3MnO3/SrTiO3 bicrystal tunnel junctions.Can the fairly simple model presented by Stoner and Wohlfart in 1948 [1] provide insights in the processes that occur in manganite bicrystal grain boundary junctions? In the following we show how the coherent rotation of the magnetization vector can explain the characteristic features in the field dependence of the magnetoresistance.Recently, a substantial low-field magnetoresistance was observed in grain boundaries of perovskite manganites [2,3] and other half-metallic ferromagnets [4,5]. In order to understand and exploit this effect several studies have used bicrystal grain boundary junctions [6,7,8]. Since bicrystals are samples with well defined crystal orientations with respect to an interface, they are in a way ideal systems for studies of the behaviour of magnetic tunnel junctions. Traditionally, the conductivity of magnetic tunnel junctions is compared with Julliere's model [9], in which the tunneling magnetoresistance is determined by the spin polarization of the electrodes. A more realistic scenario was considered by Slonczewski [10], who used a method to match the wave functions across the tunneling barrier. He derived an expression for direct tunneling through the interface which includes the angle between the directions of the magnetization of the electrodes.

show abstract

“…It was shown that the presence of grain boundaries in the polycrystalline manganites leads to a large MR effect over a wide temperature range below the Curie temperature (T C ), whereas the CMR of the single-crystalline materials is restricted to a narrower temperature range just around T C [9][10][11]. On the other hand, the influence of structural quench disorder on the magnetic ordering is still poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Magnetic and transport properties controlled by structural disorder in La0.7Ca0.3MnO3 films

Prokhorov

Komashko

Kaminsky

et al. 2004

Low Temperature Physics

View full text Add to dashboard Cite

The magnetic properties of an amorphous, a partially-disordered, and a lattice-strained crystalline La 07 . Ca 03 . MnO 3 film are investigated. It is shown that the amorphous film exhibits Curie-Weiss-type paramagnetism with the effective magnetic moment of 4.2 m B /Mn ion and a small ferromagnetic contribution governed by the formation of a quasi-two-dimensional crystalline interfacial inclusions. The crystalline film with nanocrystalline randomly-oriented inclusions demonstrates a superposition of ferromagnetic (in the crystalline matrix) and superparamagnetic (in the inclusions) nature. The fitted average size of the superparamagnetic particles in the case of a Langevin function is coincident with that of the nanocrystalline clusters reveated in high-resolution electron-microscopy images. An increase in the applied magnetic field leads to a reduction in the average magnetic moment of superparamagnetic particles, which is due to an enhancement of the ferromagnetic coupling between the individual randomly-oriented crystallites. The completely crystalline film undergoes only a ferromagnetic transition with a saturation magnetization at 5 K of 2.73 m B /Mn ion.

show abstract

Physics of grain boundaries in the colossal magnetoresistance manganites

Cited by 186 publications

References 38 publications

The effect of grain size on electrical transport and magnetic properties of La0.9Te0.1MnO3

The effect of grain size on electrical transport and magnetic properties of La0.9Te0.1MnO3

Stoner–Wohlfarth model applied to bicrystal magnetoresistance hysteresis

Magnetic and transport properties controlled by structural disorder in La0.7Ca0.3MnO3 films

Contact Info

Product

Resources

About