Vertical organic spin valves in perpendicular magnetic fields

Abstract

We report the results of magnetoresistance measurements in vertical organic spin valves with the magnetic field oriented perpendicular to the layer stack. The magnetoresistance measurements were performed after carefully preparing either parallel or antiparallel in-plane magnetization states of the magnetic electrodes in order to observe traces of Hanle precession. Due to the low mobility in organic semiconductors the transit time of spin polarized carriers should allow for precession of the spins in perpendicular fields which in statistical average would quench the magnetoresistance. However, in none of the experiments we do observe any change in resistance while sweeping the perpendicular field, up to the point where the electrode's magnetization starts to reorient. This absence of Hanle type effects indicates that the magnetoresistance is not based on the injection of spin polarized electrons into the organic semiconductor but rather on tunneling through pinholes superimposed with tunneling anisotropic magnetoresistance.

14 pages, 7 figures

References in corpus (3)

• Electrical Detection of Spin Transport in Lateral Ferromagnet-Semiconductor Devices
• Coherent spin transport through a 350-micron-thick Silicon wafer
• Hanle effect missing in a prototypical organic spintronic device

Cited by in corpus (12)

• Controlling magnetoresistance by oxygen impurities in Mq3-based molecular spin valves
• Resistive Switching and Voltage Induced Modulation of Tunneling Magnetoresistance in Nanosized Perpendicular Organic Spin Valves
• Hyperfine-induced spin relaxation of a diffusively moving carrier in low dimensions: implications for spin transport in organic semiconductors
• Nanosized Vertical Organic Spin-Valves
• Spin transport with traps: dramatic narrowing of the Hanle curve
• Giant fluctuations of local magnetoresistance of organic spin valves and non-hermitian 1D Anderson model
• Dynamic spin polarization in organic semiconductors with intermolecular exchange interaction
• Magnetoresistance in organic spintronic devices: the role of nonlinear effects
• Quantum dynamics of nuclear spins and spin relaxation in organic semiconductors
• Oxygen doping and polaron magnetic coupling in Alq${}_3$ films
• Spin excitations in systems with hopping electron transport and strong position disorder in a large magnetic field
• Distinguishing spin pumping from spin rectification in organic semiconductor-based lateral spin pumping device architectures