Nature of magnetism in copper-doped oxides: ZrO2, TiO2, MgO, SiO2, Al2O3, and ZnO

Abstract

The nature of magnetism in 10% Cu-doped ZrO2, TiO2, MgO, SiO2, and Al2O3 is investigated using superconducting quantum interference device magnetometry and electron magnetic resonance (EMR). The doping was done by the incipient wetness impregnation technique. X-ray diffraction studies showed the presence of some CuO notably in TiO2, SiO2, and Al2O3. However, EMR yielded typical Cu2+ spectra in all the samples, resulting from some doping. Magnetic field (H) and temperature (T) dependences of the magnetization (M) show only paramagnetism in these oxides in contrast to ferromagnetism with Tc=380K observed in Cu∕ZnO. Concentrations x of Cu2+ doped into the oxides are determined from the M vs T and M vs H data, showing Cu∕ZrO2 with the largest x and hence largest magnetization.

Role of defects in one-step synthesis of Cu-doped ZnO nano-coatings by electrodeposition method with enhanced magnetic and electrical properties

“…This development rooted back in 1998 when Ohno et al [1] reported the existence of ferromagnetism in Mndoped GaAs at a temperature greater than 100 K. Earlier metal oxides like TiO 2 [2], ZnO [2], SnO 2 [3], and In 2 O 3 [2] were doped with transition metals (TM) such as Co [4,5], Mn [6], Fe [7], Cu [8,9], Ti [10], and V [10] and also surface functionalized with organic molecules [11] to create high-moment DMS materials. Among metal oxides, ZnO is widely used in optoelectronic and spintronic applications [12][13][14][15].…”

Origin of ferromagnetism via hole doping in SnO2: First-principles calculation

“…Intrinsic FM is often controversial and difficult to be stabilized or controlled. It strongly depends on the sample history; samples grown under similar conditions may exhibit different magnetic properties [12]. Until now, there is no clear consensus on the mechanism of the observed unexpected d 0 magnetism.…”

Ferromagnetism in ZnO doped with Non-Magnetic Elements

“…(3) Cu. ZnO doped with Cu has been proven to possess ferromagnetism and it is well studied [9]. Here, we only concentrate on the first two groups.…”