Electrodeposited Co doped Cu2O as a Diluted Magnetic Semiconductor

I. S. BRANDT; ENIO LIMA JR.; M. A. TUMELERO; J. J. S. ACUÑA; D. L. DA SILVA; R. DEBASTIANI; J. F. DIAS; A. D. C. VIEGAS; R. D. ZYSLER; A. A. PASA

Dallas

Encuentro; APS March Meeting 2011; 2011

APS

Cu2O is a p-type semiconductor with direct band gap of ~2.17 eV that is potentially considered for application in solar cells [1], catalysts [2], and spin transistors [3]. When doped with Co, Cu2O can be considered as a diluted magnetic semiconductor (DMS) [4], as will be discussed in this contribution. We have studied the magnetic properties of room temperature electrodeposited Cu2O layers doped with Co. These layers were grown from electrolytes containing lactic acid and copper sulfate, with the addition of cobalt sulfate for the doping process, which leads to a maximum cobalt concentration of 0.1 at.%, as measured with Particle Induced X-Ray Emission (PIXE). The deposits showed an anhysteretic ferromagnetic behavior at 5 and 300 K and saturation magnetization proportional to the concentration of cobalt sulfate in the electrolyte, as observed with Superconducting Quantum Interference Device (SQUID) and Vibrating Sample Magnetometry (VSM). The decrease in the lattice parameter and electric resistivity with the simultaneous increase of the band gap, as a function of the doping level, point out to the Co incorporation to the growing layers as individual atoms in substitutional positions. In addition, no evidences for the existence of superparamagnetic particles and contaminations were observed from Zero Field Cooling (ZFC) and Field Cooling (FC) curves, High Resolution Transmission Electron Microscopy (HRTEM) images, and Electron Paramagnetic Resonance (EPR) measurements. The magnetization curves point to the direction that the magnetization process in Co doped Cu2O is dominated by dipole interactions [5]. A promising Curie temperature for spintronic application of 550 K was determined with a Faraday balance (FB).