The normal-state resistivity of grain boundaries in YBa2Cu3O7−δ

Abstract

Using an optimized bridge geometry we have been able to make accurate measurements of the properties of YBa 2 Cu 3 O 7-d grain boundaries above T c .The results show a strong dependence of the change of resistance with temperature on grain boundary angle. Analysis of our results in the context of band-bending at the boundary allows us to estimate the height of the potential barrier present at the grain boundary interface.

Electrical Transport and Noise Properties of [100]-Tilt ${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7{-}{\rm x}}$ Grain-Boundary Junctions With High $I_{c}R_{n}$ Product

“…Actually, the tunnel barrier is considered as consisting of three layers: the structurally distorted interface in the middle and two adjacent charge-depleted layers of undistorted material [1], [4], [17]. To include low-frequency voltage noise into this band-bending model, the fluctuations of trapped charge at the structural interface might be considered like in semiconductor grain boundaries [18].…”

Normal-state properties of high-angle grain boundaries in(Y,Ca)Ba2Cu3OMennema1, Ransley2, Burnell3 et al. 2005Phys. Rev. BSelf Cite7080View full textAdd to dashboardCite

“…17 It was found that the behaviour is Within the framework of this model, the barrier height is associated with the magnitude of the transport current, whereas the trapezoidal shape is linked with its temperature dependence. The temperature dependence can be explained by taking into account that, with increasing temperature, charge carriers will have a higher average energy, and will, due to the trapezoidal potential barrier, encounter a narrower effective tunnel barrier.…”

“…18 For this reason, the Wheatstone bridge measurement technique was developed, originally for grain boundaries in CMR materials 19 and later for grain boundaries in YBa 2 Cu 3 O 7-δ . [16][17][18] If the bridge structure is aligned with a grain boundary, the symmetry of the geometry ensures that all the resistance contributions balance to zero except for those arising from the grain boundary. In order to increase accuracy of the method, a Wheatstone bridge geometry that straddles the grain boundary 20 times (per arm) was applied.…”

Anisotropic distributions of electrical currents in high-T c grain-boundary junctions

“…Among a variety of possible crystallographic orienta tions of grains forming a boundary, the [001] tilt GB (see Fig. 1a) had been studied the most intensively with an emphases on the effect of order parameter symmetry and the mechanisms of charge transfer across the GB interface [1,2,[7][8][9][10][11][12][13][14][15].Recently, [100] tilt high T c GB junctions with mutually tilted c axis's (see Fig. 1b) have been fabri cated [16][17][18][19][20][21][22][23][24][25] with an order of magnitude lower GB meandering and up to a threefold increase of the I c R n values [16][17][18][19].…”